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Investment Risks
Jan. 28, 2026
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities,

including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP FUND - Class F Prospectus | SIMT Large Cap Fund | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources

and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities and/or value stocks may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market.

Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP VALUE FUND - Class F Prospectus | SIMT LARGE CAP VALUE FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities and/or growth stocks may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses. As a result, shareholders will be subject to two layers of fees and expenses with respect to investments in the Fund.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk and liquidity risk are described below and market risk is described above. Many OTC derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts is also subject to credit risk and valuation risk. Credit risk is the risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Long/Short Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Long/Short Risk — The Fund seeks long exposure to certain financial instruments and short exposure to certain other financial instruments. There is no guarantee that the returns on the Fund's long or short positions will produce positive returns and the Fund could lose money if either or both the Fund's long and short positions produce negative returns.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Non-Diversified Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Non-Diversified Risk — The Fund is non-diversified, which means that it may invest in the securities of relatively few issuers. As a result, the Fund may be more susceptible to a single adverse economic or political occurrence affecting one or more of these issuers and may experience increased volatility due to its investments in those securities. However, the Fund intends to satisfy the asset diversification requirements under the Code for classification as a RIC.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater

potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Active Management Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Active Management Risk — The Fund is subject to the risk that the Adviser's judgments about the attractiveness, value, or potential appreciation of the Fund's investments may prove to be incorrect. If the investments selected and strategies employed by the Fund fail to produce the intended results, the Fund could underperform in comparison to other funds with similar objectives and investment strategies.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Quantitative Investing Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Quantitative Investing Risk — A quantitative investment style generally involves the use of computers to implement a systematic or rules-based approach to selecting investments based on specific measurable factors. Due to the significant role technology plays in such strategies, they carry the risk of unintended or unrecognized issues or flaws in the design, coding, implementation or maintenance of the computer programs or technology used in the development and implementation of the quantitative strategy.
LARGE CAP GROWTH FUND - Class F Prospectus | SIMT LARGE CAP GROWTH FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that its investment approach, which attempts to replicate the performance of the Russell 1000 Index, may underperform other segments of the equity markets or the equity markets as a whole. The Fund is also subject to the risk that large capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Tracking Error Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tracking Error Risk — The risk that the Fund's performance may vary substantially from the performance of the benchmark index it tracks as a result of cash flows, Fund expenses, imperfect correlation between the Fund's investments and the index's components and other factors.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts is subject to leverage risk, correlation risk, liquidity risk and market risk. Market risk is described above, and leverage risk and liquidity risk are described below. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Non-Diversified Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Non-Diversification Risk — In seeking to track the Index, the Fund may become non-diversified as a result of a change in relative market capitalization or index weighting of one or more constituents of the Index. A non-diversified fund generally invests a greater portion of its assets in the securities of one or more issuers and invests overall in a smaller number of issuers than a diversified fund. When it is non-diversified, the Fund may be more sensitive to a single economic, business, political, regulatory, or other occurrence, which may negatively impact the Fund's performance and result in greater fluctuation in the value of the Fund's shares.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
LARGE CAP INDEX FUND - Class F Prospectus | SIMT Large Cap Index Fund | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
TAX-MANAGED LARGE CAP FUND - Class F Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that the Fund's investment approach, which attempts to replicate the performance of the S&P 500 Index, may underperform other segments of the equity markets or the equity markets as a whole.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Tracking Error Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tracking Error Risk — The risk that the Fund's performance may vary substantially from the performance of the benchmark index it tracks as a result of cash flows, Fund expenses, imperfect correlation between the Fund's investments and the benchmark and other factors.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Non-Diversified Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Non-Diversification Risk — In seeking to track the S&P 500 Index, the Fund may become non-diversified as a result of a change in relative market capitalization or index weighting of one or more constituents of the Index. A non-diversified fund generally invests a greater portion of its assets in the securities of one or more issuers and invests overall in a smaller number of issuers than a diversified fund. When it is non-diversified, the Fund may be more sensitive to a single economic, business, political, regulatory, or other occurrence, which may negatively impact the Fund's performance and result in greater fluctuation in the value of the Fund's shares.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
S&P 500 INDEX FUND - Class F Prospectus | SIMT S&P 500 Index Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated

in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP FUND - Class F Prospectus | SIMT Small Cap Fund | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities and/or value stocks may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP VALUE FUND - Class F Prospectus | SIMT SMALL CAP VALUE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities and/or growth stocks may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP GROWTH FUND - Class F Prospectus | SIMT SMALL CAP GROWTH FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small or medium capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
TAX-MANAGED SMALL/MID CAP FUND - Class F Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies.

Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities of medium capitalization companies may underperform other segments of the equity markets or the equity markets as a whole.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to

directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MID-CAP FUND - Class F Prospectus | SIMT MID CAP FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value

being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
U.S. MANAGED VOLATILITY FUND - Class F Prospectus | SIMT US MANAGED VOLATILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts and forward contracts is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Many OTC derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same

type of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
GLOBAL MANAGED VOLATILITY FUND - Class F Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product

lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
Tax-Managed Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed Managed Volatility Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment

in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market,

economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
Tax-Managed International Managed Volatility Fund - Class F Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. The Fund's investments are concentrated in issuers conducting business in the real estate industry, and therefore the Fund is subject to risks associated with legislative or regulatory changes, adverse market conditions and/or increased competition affecting that industry.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that the securities of issuers in the real estate industry may underperform other segments of the equity markets or the equity markets as a whole.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Warrants and Rights Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants and Rights Risk — Warrants and rights may lack a liquid secondary market for resale. The prices of warrants and rights may fluctuate as a result of speculation or other factors. Warrants and rights can provide a greater potential for profit or loss than an equivalent investment in the underlying security. Prices of warrants and rights do not necessarily move in tandem with the prices of their underlying securities and are highly volatile and speculative investments. If a warrant or right expires without being exercised, the Fund will lose any amount paid for the warrant or right.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
REAL ESTATE FUND - Class F Prospectus | SIMT REAL ESTATE FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization REITs and other companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are

heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that U.S. fixed income securities may underperform other segments of the fixed income markets or the fixed income markets as a whole.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in

comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described above. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CORE FIXED INCOME FUND - Class F Prospectus | SIMT CORE FIXED INCOME FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to its active positions in currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar

value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that high yield fixed income securities may underperform other segments of the fixed income markets or the fixed income markets as a whole.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is

speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Collateralized Debt Obligations and Collateralized Loan Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations and Collateralized Loan Obligations Risk — CDOs and CLOs are securities backed by an underlying portfolio of debt and loan obligations, respectively. CDOs and CLOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO and CLO securities as a class. The risks of investing in CDOs and CLOs depend largely on the tranche invested in and the type of the underlying debts and loans in the tranche of the CDO or CLO, respectively, in which the Fund invests. CDOs and CLOs also carry risks including, but not limited to, interest rate risk, which is described above, and credit risk, which is described below. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs or CLOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's or CLO's expenses.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower of the loan and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are

described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
HIGH YIELD BOND FUND - Class F Prospectus | SIMT HIGH YIELD BOND FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Concentration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Concentration Risk — A downturn in the financial services industry would impact the Fund more than a portfolio that does not concentrate in securities issued by companies in the financial services industry.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Financial Services Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Financial Services Industry Risk — The Fund's portfolio is concentrated in investments in securities issued by companies in the financial services industry. The financial services industry is subject to extensive government regulation. Profitability is largely dependent on the availability and cost of capital, and can fluctuate significantly when interest rates change. Financial services companies are highly dependent on short-term interest rates and typically will be adversely affected by economic downturns or changes in banking regulations.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Repurchase Agreement Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreement Risk — Although the Fund's repurchase agreement transactions will be fully collateralized at all times, they generally create leverage and involve some counterparty risk to the Fund whereby a defaulting counterparty could delay or prevent the Fund's recovery of collateral.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Conservative Income Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities usually respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors that adversely affect issuers of municipal obligations than a mutual fund

that does not have as great a concentration in municipal obligations. Municipal obligations may be underwritten or guaranteed by a relatively small number of financial services firms, so changes in the municipal securities market that affect those firms may decrease the availability of municipal instruments in the market, thereby making it difficult for the Sub-Adviser to identify and obtain appropriate investments for the Fund's portfolio. Also, there may be economic or political changes that impact the ability of issuers of municipal securities to repay principal and to make interest payments on securities owned by the Fund. Any changes in the financial condition of municipal issuers may also adversely affect the value of the Fund's securities.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Call Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Call Risk — Issuers of callable bonds may call (redeem) securities with higher coupons or interest rates before their maturity dates. The Fund may be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund's income. Bonds may be called due to falling interest rates or non-economical circumstances.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund will rely on the opinion of issuers' bond counsel on the tax-exempt status of interest on municipal bond obligations. Neither the Fund nor its Sub-Advisers will independently review the bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its shareholders to substantial tax liabilities. The Fund may invest a portion of its assets in securities that generate income that is subject to federal, state and local income tax, including the federal alternative minimum tax.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The Fund could lose money if the issuer or guarantor of a portfolio security or a counterparty to a contract fails to make timely payment or otherwise honor its obligations. If the Fund purchases securities supported by credit enhancements from banks and other financial institutions, changes in the credit quality of these institutions could cause losses to the Fund and affect its share price.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Repurchase Agreement Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreement Risk — Although the Fund's repurchase agreement transactions will be fully collateralized at all times, they generally create leverage and involve some counterparty risk to the Fund whereby a defaulting counterparty could delay or prevent the Fund's recovery of collateral.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
TAX-FREE CONSERVATIVE INCOME FUND - Class F Prospectus | SIMT Tax-Free Conservative Income Fund | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — An investment in the Fund is subject to income risk, which is the possibility that the Fund's yield will decline due to falling interest rates.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, generally will fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The Fund is also subject to the risk that the Fund's securities may underperform other segments of the markets or the markets as a whole.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
REAL RETURN FUND - Class F Prospectus | SIMT Real Return Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments,

central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, generally will fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Below Investment Grade Securities Risk (Junk Bonds) [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities Risk (Junk Bonds) — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. These risks may be increased in foreign and emerging markets.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that: (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income (when combined with its other investments that produce non-qualifying income) from such investments that do not generate qualifying income, to a maximum of 10% of its gross income to permit the Fund to qualify as a regulated investment company (RIC) under Subchapter M of the Internal Revenue Code of 1986, as amended (the Code). Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.

The Fund will gain most of its exposure to the commodities markets through its investment in the Subsidiary, which invests in commodity investments and derivative instruments. The Fund's investment in the Subsidiary is expected to provide the Fund with exposure to the commodities markets within the limitations of the federal tax requirements of the Code for qualification as a RIC. The Fund expects its income attributable to its investment in the Subsidiary to be treated as "qualifying income" for tax purposes. The Adviser will ensure that no more than 25% of the Fund's assets are invested in the Subsidiary.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Investment Company and Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company and Exchange-Traded Funds Risk — When the Fund invests in an investment company, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. In addition, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Investment in the Subsidiary Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment in the Subsidiary Risk — The Subsidiary is not registered under the Investment Company Act of 1940, as amended (the 1940 Act) and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all of the protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary, respectively, are organized, could result in the inability of the Fund and/or the Subsidiary to operate as intended and could negatively affect the Fund and its shareholders.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options, forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above and liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Market risk is the risk that the market value of an investment may move up

and down, sometimes rapidly and unpredictably. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the seller would like. The seller may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as

"covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. Reinvesting proceeds received from short selling may create leverage, which can amplify the effects of market volatility on the Fund's share price. In addition, shorting a future contract may require posting only a margin that may amount to less than the notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities

and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Repurchase Agreement Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreement Risk — Although repurchase agreement transactions must be fully collateralized at all times, they generally create leverage and involve some counterparty risk to the Fund whereby a defaulting counterparty could delay or prevent the Fund's recovery of collateral.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
DYNAMIC ASSET ALLOCATION FUND - Class F Prospectus | SIMT Dynamic Asset Allocation Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to the Fund's active positions in currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Arbitrage Strategies Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Arbitrage Strategies Risk — Arbitrage strategies involve engaging in transactions that attempt to exploit price differences of identical, related or similar securities on different markets or in different forms. The Fund may realize losses or a reduced rate of return if underlying relationships among securities in which it takes investment positions change in an adverse manner or if a transaction is unexpectedly terminated or delayed. Trading to seek short-term capital appreciation can be expected to cause the Fund's portfolio turnover rate to be substantially higher than that of the average equity-oriented investment company.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Directional or Tactical Strategies Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Directional or Tactical Strategies Risk — Directional or tactical strategies usually use long and short positions, which entail predicting the direction that particular securities or sectors or the overall market might move. Directional or tactical strategies may utilize leverage and hedging. There may be a significant risk of loss if the Fund's judgment is incorrect as to the direction, timing or extent of expected movements of particular securities or sectors or the market as a whole.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Event-Driven Strategies Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Event-Driven Strategies Risk — Event-driven strategies involve making evaluations and predictions about both the likelihood that a particular event in the life of a company will occur and the impact such an event will have on the value of the company's securities. The transaction in which such a company is involved may be unsuccessful, take considerable time (or longer than anticipated) or may result in a distribution of cash or a new security, the value of which may be less than the purchase price of the company's security. If an anticipated transaction does not occur, the Fund may be required to sell its securities at a loss.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower of the loan and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Distressed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Distressed Securities Risk — Distressed securities frequently do not produce income while they are outstanding and may require the Fund to bear certain extraordinary expenses in order to protect and recover its investment. Distressed securities are at high risk for default.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income from such investments that do not generate qualifying

income, to a maximum of 10% of its gross income (when combined with its other investments that produce non-qualifying income) to permit the Fund to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code of 1986, as amended. Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Investment Company and Exchange-Traded Funds (ETFs) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company and Exchange-Traded Funds (ETFs) Risk — When the Fund invests in an investment company, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. In addition, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options, forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above and liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. In addition, shorting a future contract may require posting only a margin that may amount to less than the notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Exchange-Traded Notes (ETNs) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes (ETNs) Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-STRATEGY ALTERNATIVE FUND - Class F Prospectus | SIMT Multi-Strategy Alternative Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to its active positions in currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.

LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities,

including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP FUND - Class I Prospectus | SIMT Large Cap Fund | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources

and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities and/or value stocks may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market.

Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP VALUE FUND - Class I Prospectus | SIMT LARGE CAP VALUE FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities and/or growth stocks may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses. As a result, shareholders will be subject to two layers of fees and expenses with respect to investments in the Fund.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk and liquidity risk are described below and market risk is described above. Many OTC derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts is also subject to credit risk and valuation risk. Credit risk is the risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Long/Short Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Long/Short Risk — The Fund seeks long exposure to certain financial instruments and short exposure to certain other financial instruments. There is no guarantee that the returns on the Fund's long or short positions will produce positive returns and the Fund could lose money if either or both the Fund's long and short positions produce negative returns.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Non-Diversified Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Non-Diversified Risk — The Fund is non-diversified, which means that it may invest in the securities of relatively few issuers. As a result, the Fund may be more susceptible to a single adverse economic or political occurrence affecting one or more of these issuers and may experience increased volatility due to its investments in those securities. However, the Fund intends to satisfy the asset diversification requirements under the Code for classification as a RIC.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater

potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Active Management Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Active Management Risk — The Fund is subject to the risk that the Adviser's judgments about the attractiveness, value, or potential appreciation of the Fund's investments may prove to be incorrect. If the investments selected and strategies employed by the Fund fail to produce the intended results, the Fund could underperform in comparison to other funds with similar objectives and investment strategies.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Quantitative Investing Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Quantitative Investing Risk — A quantitative investment style generally involves the use of computers to implement a systematic or rules-based approach to selecting investments based on specific measurable factors. Due to the significant role technology plays in such strategies, they carry the risk of unintended or unrecognized issues or flaws in the design, coding, implementation or maintenance of the computer programs or technology used in the development and implementation of the quantitative strategy.
LARGE CAP GROWTH FUND - Class I Prospectus | SIMT LARGE CAP GROWTH FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that the Fund's investment approach, which attempts to replicate the performance of the S&P 500 Index, may underperform other segments of the equity markets or the equity markets as a whole.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Tracking Error Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tracking Error Risk — The risk that the Fund's performance may vary substantially from the performance of the benchmark index it tracks as a result of cash flows, Fund expenses, imperfect correlation between the Fund's investments and the benchmark and other factors.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Non-Diversified Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Non-Diversification Risk — In seeking to track the S&P 500 Index, the Fund may become non-diversified as a result of a change in relative market capitalization or index weighting of one or more constituents of the Index. A non-diversified fund generally invests a greater portion of its assets in the securities of one or more issuers and invests overall in a smaller number of issuers than a diversified fund. When it is non-diversified, the Fund may be more sensitive to a single economic, business, political, regulatory, or other occurrence, which may negatively impact the Fund's performance and result in greater fluctuation in the value of the Fund's shares.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
S&P 500 Index Fund - Class I Prospectus | SIMT S&P 500 Index Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated

in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP FUND - Class I Prospectus | SIMT Small Cap Fund | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities and/or value stocks may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP VALUE FUND - Class I Prospectus | SIMT SMALL CAP VALUE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities and/or growth stocks may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP GROWTH FUND - Class I Prospectus | SIMT SMALL CAP GROWTH FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities of medium capitalization companies may underperform other segments of the equity markets or the equity markets as a whole.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to

directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MID-CAP FUND - Class I Prospectus | SIMT MID CAP FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
U.S. MANAGED VOLATILITY FUND - Class I Prospectus | SIMT US MANAGED VOLATILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts and forward contracts is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Many OTC derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same

type of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
GLOBAL MANAGED VOLATILITY FUND - Class I Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. The Fund's investments are concentrated in issuers conducting business in the real estate industry, and therefore the Fund is subject to risks associated with legislative or regulatory changes, adverse market conditions and/or increased competition affecting that industry.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that the securities of issuers in the real estate industry may underperform other segments of the equity markets or the equity markets as a whole.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Warrants and Rights Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants and Rights Risk — Warrants and rights may lack a liquid secondary market for resale. The prices of warrants and rights may fluctuate as a result of speculation or other factors. Warrants and rights can provide a greater potential for profit or loss than an equivalent investment in the underlying security. Prices of warrants and rights do not necessarily move in tandem with the prices of their underlying securities and are highly volatile and speculative investments. If a warrant or right expires without being exercised, the Fund will lose any amount paid for the warrant or right.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
REAL ESTATE FUND - Class I Prospectus | SIMT REAL ESTATE FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization REITs and other companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are

heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that U.S. fixed income securities may underperform other segments of the fixed income markets or the fixed income markets as a whole.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in

comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described above. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CORE FIXED INCOME FUND - Class I Prospectus | SIMT CORE FIXED INCOME FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to its active positions in currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities

denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that high yield fixed income securities may underperform other segments of the fixed income markets or the fixed income markets as a whole.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is

speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Collateralized Debt Obligations and Collateralized Loan Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations and Collateralized Loan Obligations Risk — CDOs and CLOs are securities backed by an underlying portfolio of debt and loan obligations, respectively. CDOs and CLOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO and CLO securities as a class. The risks of investing in CDOs and CLOs depend largely on the tranche invested in and the type of the underlying debts and loans in the tranche of the CDO or CLO, respectively, in which the Fund invests. CDOs and CLOs also carry risks including, but not limited to, interest rate risk, which is described above, and credit risk, which is described below. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs or CLOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's or CLO's expenses.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower of the loan and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are

described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
HIGH YIELD BOND FUND - Class I Prospectus | SIMT HIGH YIELD BOND FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, generally will fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The Fund is also subject to the risk that the Fund's securities may underperform other segments of the markets or the markets as a whole.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
REAL RETURN FUND - Class I Prospectus | SIMT Real Return Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments,

central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities,

including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP FUND - Class Y Prospectus | SIMT Large Cap Fund | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and

may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities and/or value stocks may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market.

Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP VALUE FUND - Class Y Prospectus | SIMT LARGE CAP VALUE FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities and/or growth stocks may underperform other segments of the equity markets or the equity markets as a whole.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses. As a result, shareholders will be subject to two layers of fees and expenses with respect to investments in the Fund.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk and liquidity risk are described below and market risk is described above. Many OTC derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts is also subject to credit risk and valuation risk. Credit risk is the risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Long/Short Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Long/Short Risk — The Fund seeks long exposure to certain financial instruments and short exposure to certain other financial instruments. There is no guarantee that the returns on the Fund's long or short positions will produce positive returns and the Fund could lose money if either or both the Fund's long and short positions produce negative returns.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Non-Diversified Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Non-Diversified Risk — The Fund is non-diversified, which means that it may invest in the securities of relatively few issuers. As a result, the Fund may be more susceptible to a single adverse economic or political occurrence affecting one or more of these issuers and may experience increased volatility due to its investments in those securities. However, the Fund intends to satisfy the asset diversification requirements under the Code for classification as a RIC.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater

potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Active Management Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Active Management Risk — The Fund is subject to the risk that the Adviser's judgments about the attractiveness, value, or potential appreciation of the Fund's investments may prove to be incorrect. If the investments selected and strategies employed by the Fund fail to produce the intended results, the Fund could underperform in comparison to other funds with similar objectives and investment strategies.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Quantitative Investing Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Quantitative Investing Risk — A quantitative investment style generally involves the use of computers to implement a systematic or rules-based approach to selecting investments based on specific measurable factors. Due to the significant role technology plays in such strategies, they carry the risk of unintended or unrecognized issues or flaws in the design, coding, implementation or maintenance of the computer programs or technology used in the development and implementation of the quantitative strategy.
LARGE CAP GROWTH FUND - Class Y Prospectus | SIMT LARGE CAP GROWTH FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that large capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
TAX-MANAGED LARGE CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED LARGE CAP FUND | Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Medium Capitalization Risk — The risk that medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In

particular, medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, medium capitalization stocks may be more volatile than those of larger companies. Medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP FUND - Class Y Prospectus | SIMT Small Cap Fund | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities and/or value stocks may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP VALUE FUND - Class Y Prospectus | SIMT SMALL CAP VALUE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Small Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small Capitalization Risk — Smaller capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization stocks may be more volatile than those of larger companies. Small capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small capitalization securities and/or growth stocks may underperform other segments of the equity markets or the equity markets as a whole.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
SMALL CAP GROWTH FUND - Class Y Prospectus | SIMT SMALL CAP GROWTH FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that small or medium capitalization securities may underperform other segments of the equity markets or the equity markets as a whole.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
TAX-MANAGED SMALL/MID CAP FUND - Class Y Prospectus | SIMT TAX-MANAGED SMALL/MID CAP FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities of medium capitalization companies may underperform other segments of the equity markets or the equity markets as a whole.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value

being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MID-CAP FUND - Class Y Prospectus | SIMT MID CAP FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
U.S. MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT US MANAGED VOLATILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts and forward contracts is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Many OTC derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same

type of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
GLOBAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT GLOBAL MANAGED VOLATILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product

lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed Managed Volatility Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S.

dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market,

economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that securities selected as part of a managed volatility strategy may underperform other segments of the equity markets or the equity markets as a whole.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund is managed to seek to minimize tax consequences to shareholders, but there is no guarantee that the Fund will be able to operate without incurring taxable income and gains to shareholders.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-MANAGED INTERNATIONAL MANAGED VOLATILITY FUND - Class Y Prospectus | SIMT Tax-Managed International Managed Volatility Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with the direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions. The Fund's investments are concentrated in issuers conducting business in the real estate industry, and therefore the Fund is subject to risks associated with legislative or regulatory changes, adverse market conditions and/or increased competition affecting that industry.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that the securities of issuers in the real estate industry may underperform other segments of the equity markets or the equity markets as a whole.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Warrants and Rights Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants and Rights Risk — Warrants and rights may lack a liquid secondary market for resale. The prices of warrants and rights may fluctuate as a result of speculation or other factors. Warrants and rights can provide a greater potential for profit or loss than an equivalent investment in the underlying security. Prices of warrants and rights do not necessarily move in tandem with the prices of their underlying securities and are highly volatile and speculative investments. If a warrant or right expires without being exercised, the Fund will lose any amount paid for the warrant or right.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
REAL ESTATE FUND - Class Y Prospectus | SIMT REAL ESTATE FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization REITs and other companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter (OTC). OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are

heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that U.S. fixed income securities may underperform other segments of the fixed income markets or the fixed income markets as a whole.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in

comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described above. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CORE FIXED INCOME FUND - Class Y Prospectus | SIMT CORE FIXED INCOME FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to its active positions in currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities

denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The risk that high yield fixed income securities may underperform other segments of the fixed income markets or the fixed income markets as a whole.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is

speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Collateralized Debt Obligations and Collateralized Loan Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations and Collateralized Loan Obligations Risk — CDOs and CLOs are securities backed by an underlying portfolio of debt and loan obligations, respectively. CDOs and CLOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO and CLO securities as a class. The risks of investing in CDOs and CLOs depend largely on the tranche invested in and the type of the underlying debts and loans in the tranche of the CDO or CLO, respectively, in which the Fund invests. CDOs and CLOs also carry risks including, but not limited to, interest rate risk, which is described above, and credit risk, which is described below. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs or CLOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's or CLO's expenses.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower of the loan and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. When the Fund invests in an ETF, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the ETF's expenses.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Market risk is described above, and leverage risk and liquidity risk are

described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
HIGH YIELD BOND FUND - Class Y Prospectus | SIMT HIGH YIELD BOND FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Concentration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Concentration Risk — A downturn in the financial services industry would impact the Fund more than a portfolio that does not concentrate in securities issued by companies in the financial services industry.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Financial Services Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Financial Services Industry Risk — The Fund's portfolio is concentrated in investments in securities issued by companies in the financial services industry. The financial services industry is subject to extensive government regulation. Profitability is largely dependent on the availability and cost of capital, and can fluctuate significantly when interest rates change. Financial services companies are highly dependent on short-term interest rates and typically will be adversely affected by economic downturns or changes in banking regulations.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Repurchase Agreement Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreement Risk — Although the Fund's repurchase agreement transactions will be fully collateralized at all times, they generally create leverage and involve some counterparty risk to the Fund whereby a defaulting counterparty could delay or prevent the Fund's recovery of collateral.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Conservative Income Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities usually respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors that adversely affect issuers of municipal obligations than a mutual fund

that does not have as great a concentration in municipal obligations. Municipal obligations may be underwritten or guaranteed by a relatively small number of financial services firms, so changes in the municipal securities market that affect those firms may decrease the availability of municipal instruments in the market, thereby making it difficult for the Sub-Adviser to identify and obtain appropriate investments for the Fund's portfolio. Also, there may be economic or political changes that impact the ability of issuers of municipal securities to repay principal and to make interest payments on securities owned by the Fund. Any changes in the financial condition of municipal issuers may also adversely affect the value of the Fund's securities.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Call Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Call Risk — Issuers of callable bonds may call (redeem) securities with higher coupons or interest rates before their maturity dates. The Fund may be forced to reinvest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund's income. Bonds may be called due to falling interest rates or non-economical circumstances.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Taxation Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Taxation Risk — The Fund will rely on the opinion of issuers' bond counsel on the tax-exempt status of interest on municipal bond obligations. Neither the Fund nor its Sub-Advisers will independently review the bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its shareholders to substantial tax liabilities. The Fund may invest a portion of its assets in securities that generate income that is subject to federal, state and local income tax, including the federal alternative minimum tax.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The Fund could lose money if the issuer or guarantor of a portfolio security or a counterparty to a contract fails to make timely payment or otherwise honor its obligations. If the Fund purchases securities supported by credit enhancements from banks and other financial institutions, changes in the credit quality of these institutions could cause losses to the Fund and affect its share price.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Repurchase Agreement Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreement Risk — Although the Fund's repurchase agreement transactions will be fully collateralized at all times, they generally create leverage and involve some counterparty risk to the Fund whereby a defaulting counterparty could delay or prevent the Fund's recovery of collateral.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
TAX-FREE CONSERVATIVE INCOME FUND - Class Y Prospectus | SIMT Tax-Free Conservative Income Fund | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — An investment in the Fund is subject to income risk, which is the possibility that the Fund's yield will decline due to falling interest rates.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, generally will fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Investment Style Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Style Risk — The Fund is also subject to the risk that the Fund's securities may underperform other segments of the markets or the markets as a whole.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Foreign Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
REAL RETURN FUND - Class Y Prospectus | SIMT Real Return Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments,

central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, generally will fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Below Investment Grade Securities Risk (Junk Bonds) [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities Risk (Junk Bonds) — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. These risks may be increased in foreign and emerging markets.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that: (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income (when combined with its other investments that produce non-qualifying income) from such investments that do not generate qualifying income, to a maximum of 10% of its gross income to permit the Fund to qualify as a regulated investment company (RIC) under Subchapter M of the Internal Revenue Code of 1986, as amended (the Code). Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.

The Fund will gain most of its exposure to the commodities markets through its investment in the Subsidiary, which invests in commodity investments and derivative instruments. The Fund's investment in the Subsidiary is expected to provide the Fund with exposure to the commodities markets within the limitations of the federal tax requirements of the Code for qualification as a RIC. The Fund expects its income attributable to its investment in the Subsidiary to be treated as "qualifying income" for tax purposes. The Adviser will ensure that no more than 25% of the Fund's assets are invested in the Subsidiary.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Investment Company and Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company and Exchange-Traded Funds Risk — When the Fund invests in an investment company, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. In addition, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Investment in the Subsidiary Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment in the Subsidiary Risk — The Subsidiary is not registered under the Investment Company Act of 1940, as amended (the 1940 Act) and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all of the protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary, respectively, are organized, could result in the inability of the Fund and/or the Subsidiary to operate as intended and could negatively affect the Fund and its shareholders.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options, forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above and liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Market risk is the risk that the market value of an investment may move up

and down, sometimes rapidly and unpredictably. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the seller would like. The seller may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as

"covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. Reinvesting proceeds received from short selling may create leverage, which can amplify the effects of market volatility on the Fund's share price. In addition, shorting a future contract may require posting only a margin that may amount to less than the notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities

and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Repurchase Agreement Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreement Risk — Although repurchase agreement transactions must be fully collateralized at all times, they generally create leverage and involve some counterparty risk to the Fund whereby a defaulting counterparty could delay or prevent the Fund's recovery of collateral.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
DYNAMIC ASSET ALLOCATION FUND - Class Y Prospectus | SIMT Dynamic Asset Allocation Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to the Fund's active positions in currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the United States or abroad.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Arbitrage Strategies Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Arbitrage Strategies Risk — Arbitrage strategies involve engaging in transactions that attempt to exploit price differences of identical, related or similar securities on different markets or in different forms. The Fund may realize losses or a reduced rate of return if underlying relationships among securities in which it takes investment positions change in an adverse manner or if a transaction is unexpectedly terminated or delayed. Trading to seek short-term capital appreciation can be expected to cause the Fund's portfolio turnover rate to be substantially higher than that of the average equity-oriented investment company.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Directional or Tactical Strategies Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Directional or Tactical Strategies Risk — Directional or tactical strategies usually use long and short positions, which entail predicting the direction that particular securities or sectors or the overall market might move. Directional or tactical strategies may utilize leverage and hedging. There may be a significant risk of loss if the Fund's judgment is incorrect as to the direction, timing or extent of expected movements of particular securities or sectors or the market as a whole.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Event-Driven Strategies Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Event-Driven Strategies Risk — Event-driven strategies involve making evaluations and predictions about both the likelihood that a particular event in the life of a company will occur and the impact such an event will have on the value of the company's securities. The transaction in which such a company is involved may be unsuccessful, take considerable time (or longer than anticipated) or may result in a distribution of cash or a new security, the value of which may be less than the purchase price of the company's security. If an anticipated transaction does not occur, the Fund may be required to sell its securities at a loss.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed income securities that the Fund may acquire.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower of the loan and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Distressed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Distressed Securities Risk — Distressed securities frequently do not produce income while they are outstanding and may require the Fund to bear certain extraordinary expenses in order to protect and recover its investment. Distressed securities are at high risk for default.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as ADRs, are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income from such investments that do not generate qualifying

income, to a maximum of 10% of its gross income (when combined with its other investments that produce non-qualifying income) to permit the Fund to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code of 1986, as amended. Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Investment Company and Exchange-Traded Funds (ETFs) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company and Exchange-Traded Funds (ETFs) Risk — When the Fund invests in an investment company, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. In addition, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, options, forward contracts and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above and liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and the price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. In addition, shorting a future contract may require posting only a margin that may amount to less than the notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Exchange-Traded Notes (ETNs) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes (ETNs) Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-STRATEGY ALTERNATIVE FUND - Class Y Prospectus | SIMT Multi-Strategy Alternative Fund | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — Due to its active positions in currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Commodity Investments and Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity Investments and Derivatives Risk — Commodity investments and derivatives may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses. The value of a commodity investment or a derivative investment in commodities is typically based upon the

price movements of a physical commodity, a commodity futures contract or commodity index or some other readily measurable economic variable that is dependent upon changes in the value of commodities or the commodities markets. The value of these securities will rise or fall in response to changes in the underlying commodity or related benchmark or investment, changes in interest rates or factors affecting a particular industry or commodity, such as natural disasters, weather and U.S. and international economic, political and regulatory developments.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities usually respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors which adversely affect issuers of municipal obligations than a mutual fund which does not have as great a concentration in municipal obligations. Any changes in the financial condition of municipal issuers also may adversely affect the value of the Fund's securities.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that: (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such

securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as American Depositary Receipts (ADRs), are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income from such investments that do not generate qualifying income, to a maximum of 10% of its gross income (when combined with its other investments that produce non-qualifying income) to permit the Fund to qualify as a regulated investment company (RIC) under Subchapter M of the Internal Revenue Code of 1986, as amended (the Code). Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.

The Fund will gain most of its exposure to the commodities markets through its investment in a Subsidiary, which invests in commodity investments and derivative instruments. The Fund's investment in the Subsidiary is expected to provide the Fund with exposure to the commodities markets within the limitations of the federal tax requirements of Subchapter M of the Code for qualification as a RIC. The Fund expects its income attributable to its investment in the Subsidiary to be treated as "qualifying income" for tax purposes. The Adviser will ensure that no more than 25% of the Fund's assets are invested in the Subsidiary.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Investment in the Subsidiary Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment in the Subsidiary Risk — The Subsidiary is not registered under the Investment Company Act of 1940, as amended (the 1940 Act) and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all of the protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary, respectively, are organized, could result in the inability of the Fund and/or the Subsidiary to operate as intended and could negatively affect the Fund and its shareholders.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. In addition, shorting a future contract may require posting only a margin that may amount to less than notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions

when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET ACCUMULATION FUND - Class F Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions

concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities generally respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors which adversely affect issuers of municipal obligations than a mutual fund which does not have as great a concentration in municipal obligations. Any changes in the financial condition of municipal issuers also may adversely affect the value of the Fund's securities.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Master Limited Partnership (MLP) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Master Limited Partnership (MLP) Risk — Investments in units of MLPs involve risks that differ from an investment in common stock. Holders of the units of MLPs have more limited control and limited rights to vote on matters affecting the partnership. There are also certain tax risks associated with an investment in units of MLPs. In addition, conflicts of interest may exist between common unit holders, subordinated unit holders and the general partner of an MLP, including a conflict arising as a result of incentive distribution payments. The benefit the Fund derives from investment in MLP units is largely dependent on the MLPs being treated as partnerships and not as corporations for federal income tax purposes. If an MLP were classified as a corporation for federal income tax purposes, there would be a reduction in the after-tax return to the Fund of distributions from the MLP, likely causing a reduction in the value of the Fund's shares. MLP entities are typically focused in the energy, natural resources and real estate sectors of the economy. A downturn in the energy, natural resources or real estate sectors of the economy could have an adverse impact on the Fund. At times, the performance of securities of companies in the energy, natural resources and real estate sectors of the economy may lag the performance of other sectors or the broader market as a whole. The Internal Revenue Code of 1986, as amended, provides that the Fund is permitted to invest up to 25% of its assets in one or more qualified publicly traded partnerships (QPTPs), which will include certain MLPs, and treat the income allocated by such QPTPs as qualifying income for purposes of the regulated investment company annual qualifying income requirements described in the section titled "Taxes" in the SAI.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Collateralized Debt Obligations and Collateralized Loan Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations and Collateralized Loan Obligations Risk — CDOs and CLOs are securities backed by an underlying portfolio of debt and loan obligations, respectively. CDOs and CLOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO and CLO securities as a class. The risks of investing in CDOs and CLOs depend largely on the tranche invested in and the type of the underlying debts and loans in the tranche of the CDO or CLO, respectively, in which the Fund invests. CDOs and CLOs also carry risks including, but not limited to, interest rate risk and credit risk, which are described above. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs or CLOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's or CLO's expenses.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national

economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls.

Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by

interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The portfolio may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as American Depositary Receipts (ADRs), are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its share price being more volatile

than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. In addition, shorting a future contract may require posting only a margin that may amount to less than notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Private Placements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Private Placements Risk — Investment in privately placed securities may be less liquid than in publicly traded securities. Although these securities may be resold in privately negotiated transactions, the prices realized from these sales could be less than those originally paid by the Fund or less than what may be considered the fair value of such securities. Further, companies whose securities are not publicly traded may not be subject to the disclosure and other investor protection requirements that might be applicable if their securities were publicly traded.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET INCOME FUND - Class F Prospectus | SIMT MULTI-ASSET INCOME FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated

in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the U.S. or abroad.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Commodity Investments and Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity Investments and Derivatives Risk — Commodity investments and derivatives may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.

The value of a commodity investment or a derivative investment in commodities is typically based upon the price movements of a physical commodity, a commodity futures contract or commodity index or some other readily measurable economic variable that is dependent upon changes in the value of commodities or the commodities markets. The value of these securities will rise or fall in response to changes in the underlying commodity or related benchmark or investment, changes in interest rates or factors affecting a particular industry or commodity, such as natural disasters, weather and U.S. and international economic, political and regulatory developments.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities usually respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors which adversely affect issuers of municipal obligations than a mutual fund which does not have as great a concentration in municipal obligations. Any changes in the financial condition of municipal issuers also may adversely affect the value of the Fund's securities.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less

information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that: (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Collateralized Debt Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations Risk — CDOs are securities backed by an underlying portfolio of debt obligations. CDOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO securities as a class. The risks of investing in CDOs depend largely on the tranche invested in and the type of the underlying debts in the tranche of the CDO in which the Fund invests. CDOs also carry risks including, but not limited to, interest rate risk and credit risk, which are described above. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's expenses.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as American Depositary Receipts (ADRs), are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income from such investments that do not generate qualifying income, to a maximum of 10% of its gross income (when combined with its other investments that produce non-qualifying income) to permit the Fund to qualify as a regulated investment company (RIC) under Subchapter M of the Internal Revenue Code of 1986, as amended (the Code). Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.

The Fund will gain most of its exposure to the commodities markets through its investment in a Subsidiary, which invests in commodity investments and derivative instruments. The Fund's investment in the Subsidiary is expected to provide the Fund with exposure to the commodities markets within the limitations of the federal tax requirements of Subchapter M of the Code for qualification as a RIC. The Fund expects its income attributable to its investment in the Subsidiary to be treated as "qualifying income" for tax purposes. The Adviser will ensure that no more than 25% of the Fund's assets are invested in the Subsidiary.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the

Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Investment in the Subsidiary Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment in the Subsidiary Risk — The Subsidiary is not registered under the Investment Company Act of 1940, as amended (1940 Act) and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all of the protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary, respectively, are organized, could result in the inability of the Fund and/or the Subsidiary to operate as intended and could negatively affect the Fund and its shareholders.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a

negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investing in short sales may also cause the Fund to incur expenses related to borrowing securities. Reinvesting proceeds received from short selling may create leverage, which can amplify the effects of market volatility on the Fund's share price. In addition, shorting a future contract may require posting only a margin that may amount to less than the notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET INFLATION MANAGED FUND - Class F Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the U.S. or abroad.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an

investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed

securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is

the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Private Placements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Private Placements Risk — Investment in privately placed securities may be less liquid than in publicly traded securities. Although these securities may be resold in privately negotiated transactions, the prices realized from these sales could be less than those originally paid by the Fund or less than what may be considered the fair value of such securities. Further, companies whose securities are not publicly traded may not be subject to the disclosure and other investor protection requirements that might be applicable if their securities were publicly traded.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET CAPITAL STABILITY FUND - Class F Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Commodity Investments and Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity Investments and Derivatives Risk — Commodity investments and derivatives may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses. The value of a commodity investment or a derivative investment in commodities is typically based upon the

price movements of a physical commodity, a commodity futures contract or commodity index or some other readily measurable economic variable that is dependent upon changes in the value of commodities or the commodities markets. The value of these securities will rise or fall in response to changes in the underlying commodity or related benchmark or investment, changes in interest rates or factors affecting a particular industry or commodity, such as natural disasters, weather and U.S. and international economic, political and regulatory developments.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities usually respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors which adversely affect issuers of municipal obligations than a mutual fund which does not have as great a concentration in municipal obligations. Any changes in the financial condition of municipal issuers also may adversely affect the value of the Fund's securities.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that: (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such

securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as American Depositary Receipts (ADRs), are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income from such investments that do not generate qualifying income, to a maximum of 10% of its gross income (when combined with its other investments that produce non-qualifying income) to permit the Fund to qualify as a regulated investment company (RIC) under Subchapter M of the Internal Revenue Code of 1986, as amended (the Code). Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.

The Fund will gain most of its exposure to the commodities markets through its investment in a Subsidiary, which invests in commodity investments and derivative instruments. The Fund's investment in the Subsidiary is expected to provide the Fund with exposure to the commodities markets within the limitations of the federal tax requirements of Subchapter M of the Code for qualification as a RIC. The Fund expects its income attributable to its investment in the Subsidiary to be treated as "qualifying income" for tax purposes. The Adviser will ensure that no more than 25% of the Fund's assets are invested in the Subsidiary.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Investment in the Subsidiary Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment in the Subsidiary Risk — The Subsidiary is not registered under the Investment Company Act of 1940, as amended (the 1940 Act) and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all of the protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary, respectively, are organized, could result in the inability of the Fund and/or the Subsidiary to operate as intended and could negatively affect the Fund and its shareholders.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. In addition, shorting a future contract may require posting only a margin that may amount to less than notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions

when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET ACCUMULATION FUND - Class Y Prospectus | SIMT MULTI-ASSET ACCUMULATION FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Equity market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions

concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities generally respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors which adversely affect issuers of municipal obligations than a mutual fund which does not have as great a concentration in municipal obligations. Any changes in the financial condition of municipal issuers also may adversely affect the value of the Fund's securities.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Master Limited Partnership (MLP) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Master Limited Partnership (MLP) Risk — Investments in units of MLPs involve risks that differ from an investment in common stock. Holders of the units of MLPs have more limited control and limited rights to vote on matters affecting the partnership. There are also certain tax risks associated with an investment in units of MLPs. In addition, conflicts of interest may exist between common unit holders, subordinated unit holders and the general partner of an MLP, including a conflict arising as a result of incentive distribution payments. The benefit the Fund derives from investment in MLP units is largely dependent on the MLPs being treated as partnerships and not as corporations for federal income tax purposes. If an MLP were classified as a corporation for federal income tax purposes, there would be a reduction in the after-tax return to the Fund of distributions from the MLP, likely causing a reduction in the value of the Fund's shares. MLP entities are typically focused in the energy, natural resources and real estate sectors of the economy. A downturn in the energy, natural resources or real estate sectors of the economy could have an adverse impact on the Fund. At times, the performance of securities of companies in the energy, natural resources and real estate sectors of the economy may lag the performance of other sectors or the broader market as a whole. The Internal Revenue Code of 1986, as amended, provides that the Fund is permitted to invest up to 25% of its assets in one or more qualified publicly traded partnerships (QPTPs), which will include certain MLPs, and treat the income allocated by such QPTPs as qualifying income for purposes of the regulated investment company annual qualifying income requirements described in the section titled "Taxes" in the SAI.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Collateralized Debt Obligations and Collateralized Loan Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations and Collateralized Loan Obligations Risk — CDOs and CLOs are securities backed by an underlying portfolio of debt and loan obligations, respectively. CDOs and CLOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO and CLO securities as a class. The risks of investing in CDOs and CLOs depend largely on the tranche invested in and the type of the underlying debts and loans in the tranche of the CDO or CLO, respectively, in which the Fund invests. CDOs and CLOs also carry risks including, but not limited to, interest rate risk and credit risk, which are described above. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs or CLOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's or CLO's expenses.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national

economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls.

Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by

interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The portfolio may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as American Depositary Receipts (ADRs), are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its share price being more volatile

than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investment in short sales may also cause the Fund to incur expenses related to borrowing securities. In addition, shorting a future contract may require posting only a margin that may amount to less than notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Private Placements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Private Placements Risk — Investment in privately placed securities may be less liquid than in publicly traded securities. Although these securities may be resold in privately negotiated transactions, the prices realized from these sales could be less than those originally paid by the Fund or less than what may be considered the fair value of such securities. Further, companies whose securities are not publicly traded may not be subject to the disclosure and other investor protection requirements that might be applicable if their securities were publicly traded.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET INCOME FUND - Class Y Prospectus | SIMT MULTI-ASSET INCOME FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Due to the Fund's investments in securities denominated

in foreign currencies, it will be subject to the risk that currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the U.S. or abroad.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and

increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Commodity Investments and Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity Investments and Derivatives Risk — Commodity investments and derivatives may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses. The value of a commodity investment or a derivative investment in commodities is typically based upon the price movements of a physical commodity, a commodity futures contract or commodity index or some other readily measurable economic variable that is dependent upon changes in the value of commodities or the commodities markets. The value of these securities will rise or fall in response to changes in the underlying commodity or related benchmark or investment, changes in interest rates or factors affecting a particular industry or commodity, such as natural disasters, weather and U.S. and international economic, political and regulatory developments.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Commodity-Linked Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commodity-Linked Securities Risk — Investments in commodity-linked securities may be more volatile and less liquid than direct investments in the underlying commodities themselves. Commodity-related equity returns can also be affected by the issuer's financial structure or the performance of unrelated businesses.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Municipal Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Municipal Securities Risk — Municipal securities, like other fixed income securities, rise and fall in value in response to economic and market factors, primarily changes in interest rates, and actual or perceived credit quality. Rising interest rates will generally cause municipal securities to decline in value. Longer-term securities usually respond more sharply to interest rate changes than do shorter-term securities. A municipal security will also lose value if, due to rating downgrades or other factors, there are concerns about the issuer's current or future ability to make principal or interest payments. State and local governments rely on taxes and, to some extent, revenues from private projects financed by municipal securities, to pay interest and principal on municipal debt. Poor statewide or local economic results or changing political sentiments may reduce tax revenues and increase the expenses of municipal issuers, making it more difficult for them to repay principal and to make interest payments on securities owned by the Fund. Actual or perceived erosion of the creditworthiness of municipal issuers may reduce the value of the Fund's holdings. As a result, the Fund will be more susceptible to factors which adversely affect issuers of municipal obligations than a mutual fund which does not have as great a concentration in municipal obligations. Any changes in the financial condition of municipal issuers also may adversely affect the value of the Fund's securities.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that: (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Collateralized Debt Obligations Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Collateralized Debt Obligations Risk — CDOs are securities backed by an underlying portfolio of debt obligations. CDOs issue classes or "tranches" that vary in risk and yield and may experience substantial losses due to actual defaults, decrease in market value due to collateral defaults and removal of subordinate tranches, market anticipation of defaults and investor aversion to CDO securities as a class. The risks of investing in CDOs depend largely on the tranche invested in and the type of the underlying debts in the tranche of the CDO in which the Fund invests. CDOs also carry risks including, but not limited to, interest rate risk and credit risk, which are described above. For example, a liquidity crisis in the global credit markets could cause substantial fluctuations in prices for leveraged loans and high-yield debt securities and limited liquidity for such instruments. When the Fund invests in CDOs, in addition to directly bearing the expenses associated with its own operations, it may bear a pro rata portion of the CDO's expenses.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's

expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Depositary Receipts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Depositary Receipts Risk — Depositary receipts, such as American Depositary Receipts (ADRs), are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. Depositary receipts are subject to many of the risks associated with investing directly in foreign securities, including, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Tax Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Tax Risk — To the extent the Fund invests in commodities and certain commodity-linked derivative instruments directly, it will seek to restrict its income from such investments that do not generate qualifying income, to a maximum of 10% of its gross income (when combined with its other investments that produce non-qualifying income) to permit the Fund to qualify as a regulated investment company (RIC) under Subchapter M of the Internal Revenue Code of 1986, as amended (the Code). Failure to comply with the qualifying income test could have significant negative consequences to Fund shareholders.

The Fund will gain most of its exposure to the commodities markets through its investment in a Subsidiary, which invests in commodity investments and derivative instruments. The Fund's investment in the Subsidiary is expected to provide the Fund with exposure to the commodities markets within the limitations of the federal tax requirements of Subchapter M of the Code for qualification as a RIC. The Fund expects its income

attributable to its investment in the Subsidiary to be treated as "qualifying income" for tax purposes. The Adviser will ensure that no more than 25% of the Fund's assets are invested in the Subsidiary.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Investment in the Subsidiary Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment in the Subsidiary Risk — The Subsidiary is not registered under the Investment Company Act of 1940, as amended (1940 Act) and, unless otherwise noted in this prospectus, is not subject to all of the investor protections of the 1940 Act. Thus, the Fund, as an investor in the Subsidiary, will not have all of the protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the Fund and the Subsidiary, respectively, are organized, could result in the inability of the Fund and/or the Subsidiary to operate as intended and could negatively affect the Fund and its shareholders.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs will be subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Preferred Stock Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Preferred Stock Risk — Preferred stock represents an equity or ownership interest in an issuer that pays dividends at a specified rate and that has precedence over common stock in the payment of dividends. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Short Sales Risk — A short sale involves the sale of a security that the Fund does not own in the expectation of purchasing the same security (or a security exchangeable therefore) at a later date at a lower price. Short sales expose the Fund to the risk that it will be required to buy the security sold short (also known as "covering" the short position) at a time when the security has appreciated in value, thus resulting in a loss to the Fund that is potentially unlimited. Investing in short sales may also cause the Fund to incur expenses related to borrowing securities. Reinvesting proceeds received from short selling may create leverage, which can amplify the effects of market volatility on the Fund's share price. In addition, shorting a future contract may require posting only a margin that may amount to less than the notional exposure of the contract. Such a practice may exacerbate the loss in a case of adverse price action.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET INFLATION MANAGED FUND - Class Y Prospectus | SIMT MULTI-ASSET INFLATION MANAGED FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in the U.S. or abroad.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money on your investment in the Fund, just as you could with other investments.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Risk Not Insured [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Equity Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Equity Market Risk — The risk that the market value of a security may move up and down, sometimes rapidly and unpredictably. Market risk may affect a single issuer, an industry, a sector or the equity or bond market as a whole. Equity markets may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Fixed Income Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Fixed Income Market Risk — The prices of the Fund's fixed income securities respond to economic developments, particularly interest rate changes, as well as to perceptions about the creditworthiness of individual issuers, including governments and their agencies. Generally, the Fund's fixed income securities will decrease in value if interest rates rise and vice versa. In a low interest rate environment, risks associated with rising rates are heightened. Declines in dealer market-making capacity as a result of structural or regulatory changes could decrease liquidity and/or increase volatility in the fixed income markets. Markets for fixed income securities may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Similarly, environmental and public health risks, such as natural disasters, epidemics, pandemics or widespread fear that such events may occur, may impact markets adversely and cause market volatility in both the short- and long-term. In response to these events, the Fund's value may fluctuate and/or the Fund may experience increased redemptions from shareholders, which may impact the Fund's liquidity or force the Fund to sell securities into a declining or illiquid market.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Inflation Protected Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Inflation Protected Securities Risk — The value of inflation protected securities, including TIPS, will typically fluctuate in response to changes in "real" interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. Real interest rates represent nominal (or stated) interest rates reduced by the expected impact of inflation. In addition, interest payments on inflation-indexed securities will generally vary up or down along with the rate of inflation.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Real Estate Industry Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Industry Risk — Securities of companies principally engaged in the real estate industry may be subject to the risks associated with direct ownership of real estate. Risks commonly associated with the direct

ownership of real estate include fluctuations in the value of underlying properties, defaults by borrowers or tenants, changes in interest rates and risks related to general or local economic conditions.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Large Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Large Capitalization Risk — The risk that larger, more established companies may be unable to respond quickly to new competitive challenges such as changes in technology and consumer tastes. Larger companies also may not be able to attain the high growth rates of successful smaller companies.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Interest Rate Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Interest Rate Risk — The risk that a change in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. Generally, the value of the Fund's fixed income securities will vary inversely with the direction of prevailing interest rates. Changing interest rates may have unpredictable effects on the markets and may affect the value and liquidity of instruments held by the Fund. Although U.S. Government securities are considered to be among the safest investments, they are not guaranteed against price movements due to changing interest rates.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Below Investment Grade Securities (Junk Bonds) Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Below Investment Grade Securities (Junk Bonds) Risk — Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are generally more volatile than investment grade securities because the prospect for repayment of principal and interest of many of these securities is speculative. Because these securities typically offer a higher rate of return to compensate investors for these risks, they are sometimes referred to as "high yield bonds," but there is no guarantee that an investment in

these securities will result in a high rate of return. These risks may be increased in foreign and emerging markets.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Corporate Fixed Income Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Corporate Fixed Income Securities Risk — Corporate fixed income securities respond to economic developments, especially changes in interest rates, as well as to perceptions of the creditworthiness and business prospects of individual issuers.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

U.S. Government Securities Risk — Although U.S. Government securities are considered to be among the safest investments, they are still subject to the credit risk of the U.S. Government and are not guaranteed against price movements due to changing interest rates. Obligations issued by some U.S. Government agencies are backed by the U.S. Treasury, while others are backed solely by the ability of the agency to borrow from the U.S. Treasury or by the agency's own resources. No assurance can be given that the U.S. Government will provide financial support to its agencies and instrumentalities if it is not obligated by law to do so.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Convertible and Preferred Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Convertible and Preferred Securities Risk — Convertible and preferred securities have many of the same characteristics as stocks, including many of the same risks. In addition, convertible securities may be more sensitive to changes in interest rates than stocks. Convertible securities may also have credit ratings below investment grade, meaning that they carry a higher risk of failure by the issuer to pay principal and/or interest when due.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Foreign Investment/Emerging Markets Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Investment/Emerging Markets Risk — The risk that non-U.S. securities may be subject to additional risks due to, among other things, political, social and economic developments abroad, currency movements and different legal, regulatory, tax, accounting and audit environments. These additional risks may be heightened with respect to emerging market countries because political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Investments in emerging markets are subject to the added risk that information in emerging market investments may be unreliable or outdated due to differences in regulatory, accounting or auditing and financial record keeping standards, or because less information about emerging market investments is publicly available. In addition, the rights and remedies associated with emerging market investments may be different than investments in developed markets. A lack of reliable information, rights and remedies increase the risks of investing in emerging markets in comparison to more developed markets. In addition, periodic U.S. Government restrictions on investments in issuers from certain foreign countries may require the Fund to sell such investments at inopportune times, which could result in losses to the Fund.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Foreign Sovereign Debt Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Foreign Sovereign Debt Securities Risk — The risks that (i) the governmental entity that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or interest when it becomes due because of factors such as debt service burden, political constraints, cash flow problems and other national economic factors; (ii) governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments; and (iii) there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Asset-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Asset-Backed Securities Risk — Payment of principal and interest on asset-backed securities is dependent largely on the cash flows generated by the assets backing the securities. Securitization trusts generally do not have any assets or sources of funds other than the receivables and related property they own, and asset-backed securities are generally not insured or guaranteed by the related sponsor or any other entity. Asset-backed securities may be more illiquid than more conventional types of fixed-income securities that the Fund may acquire.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Mortgage-Backed Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage-Backed Securities Risk — Mortgage-backed securities are affected significantly by the rate of prepayments and modifications of the mortgage loans backing those securities, as well as by other factors such as borrower defaults, delinquencies, realized or liquidation losses and other shortfalls. Mortgage-backed

securities are particularly sensitive to prepayment risk, which is described below, given that the term to maturity for mortgage loans is generally substantially longer than the expected lives of those securities; however, the timing and amount of prepayments cannot be accurately predicted. The timing of changes in the rate of prepayments of the mortgage loans may significantly affect the Fund's actual yield to maturity on any mortgage-backed securities, even if the average rate of principal payments is consistent with the Fund's expectation. Along with prepayment risk, mortgage-backed securities are significantly affected by interest rate risk, which is described above. In a low interest rate environment, mortgage loan prepayments would generally be expected to increase due to factors such as refinancings and loan modifications at lower interest rates. In contrast, if prevailing interest rates rise, prepayments of mortgage loans would generally be expected to decline and therefore extend the weighted average lives of mortgage-backed securities held or acquired by the Fund.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Repurchase Agreements and Reverse Repurchase Agreements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Repurchase Agreements and Reverse Repurchase Agreements Risk — In the event of the insolvency of the counterparty to a repurchase agreement or reverse repurchase agreement, recovery of the repurchase price owed to the Fund or, in the case of a reverse repurchase agreement, the securities sold by the Fund, may be delayed. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. If the Fund reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Fund's yield.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Mortgage Dollar Rolls Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Mortgage Dollar Rolls Risk — Mortgage dollar rolls are transactions in which the Fund sells securities (usually mortgage-backed securities) and simultaneously contracts to repurchase substantially similar, but not identical, securities on a specified future date. If the broker-dealer to whom the Fund sells the security becomes insolvent, the Fund's right to repurchase the security may be restricted. Other risks involved in entering into mortgage dollar rolls include the risk that the value of the security may change adversely over the term of the mortgage dollar roll and that the security the Fund is required to repurchase may be worth less than the security that the Fund originally held.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Bank Loans Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Bank Loans Risk — With respect to bank loans, the Fund will assume the credit risk of both the borrower and the lender that is selling the participation in the loan. The Fund may also have difficulty disposing of bank loans because, in certain cases, the market for such instruments is not highly liquid.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Investment Company Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Investment Company Risk — When the Fund invests in an investment company, including closed-end funds and ETFs, in addition to directly bearing the expenses associated with its own operations, it will bear a pro rata portion of the investment company's expenses. Further, while the risks of owning shares of an investment company generally reflect the risks of owning the underlying investments of the investment company, the Fund may be subject to additional or different risks than if the Fund had invested directly in the underlying investments. For example, the lack of liquidity in an ETF could result in its value being more volatile than that of the underlying portfolio securities. Closed-end investment companies issue a fixed number of shares that trade on a stock exchange or over-the-counter at a premium or a discount to their net asset value. As a result, a closed-end fund's share price fluctuates based on what another investor is willing to pay rather than on the market value of the securities in the fund.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Real Estate Investment Trusts Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Real Estate Investment Trusts Risk — REITs are trusts that invest primarily in commercial real estate or real estate-related loans. The Fund's investments in REITs are subject to the risks associated with the direct ownership of real estate, which are discussed above. Some REITs may have limited diversification and may be subject to risks inherent in financing a limited number of properties.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Exchange-Traded Funds Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Funds Risk — The risks of owning shares of an ETF generally reflect the risks of owning the underlying securities the ETF is designed to track, although lack of liquidity in an ETF could result in its value being more volatile than the underlying portfolio securities. Leveraged ETFs contain all of the risks that non-leveraged ETFs present. Additionally, to the extent the Fund invests in ETFs that achieve leveraged exposure to their underlying indexes through the use of derivative instruments, the Fund will indirectly be subject to leverage risk, described above. Leveraged Inverse ETFs seek to provide investment results that match a negative multiple of the performance of an underlying index. To the extent that the Fund invests in Leveraged Inverse ETFs, the Fund will indirectly be subject to the risk that the performance of such ETF will fall as the performance of that ETF's benchmark rises. Leveraged and Leveraged Inverse ETFs often "reset" daily, meaning that they are designed to achieve their stated objectives on a daily basis. Due to the effect of compounding, their performance over longer periods of time can differ significantly from the performance (or inverse of the performance) of their underlying index or benchmark during the same period of time. These investment vehicles may be extremely volatile and can potentially expose the Fund to significant losses.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Exchange-Traded Notes Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Exchange-Traded Notes Risk — The value of an ETN is subject to the credit risk of the issuer. There may not be an active trading market available for some ETNs. Additionally, trading of ETNs may be halted or the ETN may be delisted by the listing exchange.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Derivatives Risk — The Fund's use of futures contracts, forward contracts, options and swaps is subject to market risk, leverage risk, correlation risk and liquidity risk. Leverage risk is described above. Market risk is

the risk that the market value of an investment may move up and down, sometimes rapidly and unpredictably. Liquidity risk is described below. Many over-the-counter (OTC) derivative instruments will not have liquidity beyond the counterparty to the instrument. Correlation risk is the risk that changes in the value of the derivative may not correlate perfectly with the underlying asset, rate or index. The Fund's use of forward contracts and swap agreements is also subject to credit risk and valuation risk. Credit risk is described below. Valuation risk is the risk that the derivative may be difficult to value and/or may be valued incorrectly. Each of these risks could cause the Fund to lose more than the principal amount invested in a derivative instrument. Some derivatives have the potential for unlimited loss, regardless of the size of the Fund's initial investment. The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. The Fund's use of derivatives may also increase the amount of taxes payable by shareholders. Both U.S. and non-U.S. regulators have adopted and implemented regulations governing derivatives markets, the ultimate impact of which remains unclear.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Warrants Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Warrants Risk — Warrants are instruments that entitle the holder to buy an equity security at a specific price for a specific period of time. Warrants may be more speculative than other types of investments. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. A warrant ceases to have value if it is not exercised prior to its expiration date.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Liquidity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Liquidity Risk — The risk that certain securities may be difficult or impossible to sell at the time and price that the Fund would like. The Fund may have to lower the price of the security, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Extension Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Prepayment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Prepayment Risk — The risk that, in a declining interest rate environment, fixed income securities with stated interest rates may have the principal paid earlier than expected, requiring the Fund to invest the proceeds at generally lower interest rates.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Opportunity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Opportunity Risk — The risk of missing out on an investment opportunity because the assets necessary to take advantage of it are tied up in other investments.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Private Placements Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Private Placements Risk — Investment in privately placed securities may be less liquid than in publicly traded securities. Although these securities may be resold in privately negotiated transactions, the prices realized from these sales could be less than those originally paid by the Fund or less than what may be considered the fair value of such securities. Further, companies whose securities are not publicly traded may not be subject to the disclosure and other investor protection requirements that might be applicable if their securities were publicly traded.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and taxes subject to ordinary income tax rates as opposed to more favorable capital gains rates, which may affect the Fund's performance.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Leverage Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Leverage Risk — The Fund's use of derivatives may result in the Fund's total investment exposure substantially exceeding the value of its portfolio securities and the Fund's investment returns depending substantially on the performance of securities that the Fund may not directly own. The use of leverage can amplify the effects of market volatility on the Fund's share price and may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The Fund's use of leverage may result in a heightened risk of investment loss.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Credit Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Credit Risk — The risk that the issuer of a security or the counterparty to a contract will default or otherwise become unable to honor a financial obligation.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Commercial Paper Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Commercial Paper Risk — Commercial paper is a short-term obligation with a maturity generally ranging from one to 270 days and is issued by U.S. or foreign companies or other entities in order to finance their current operations. Such investments are unsecured and usually discounted from their value at maturity. The value of commercial paper may be affected by changes in the credit rating or financial condition of the issuing entities and will tend to fall when interest rates rise and rise when interest rates fall. Asset-backed commercial paper may be issued by structured investment vehicles or other conduits that are organized to issue the commercial paper and to purchase trade receivables or other financial assets. The repayment of asset-backed commercial paper depends primarily on the cash collections received from such issuer's underlying asset portfolio and the issuer's ability to issue new asset-backed commercial paper.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Duration Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Duration Risk — The longer-term securities in which the Fund may invest tend to be more volatile than shorter-term securities. A portfolio with a longer average portfolio duration is more sensitive to changes in interest rates than a portfolio with a shorter average portfolio duration.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Income Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Income Risk — The possibility that the Fund's yield will decline due to falling interest rates.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Small and Medium Capitalization Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund may invest may be more vulnerable to adverse business or economic events than larger, more established companies. In particular, small and medium capitalization companies may have limited product lines, markets and financial resources and may depend upon a relatively small management group. Therefore, small capitalization and medium capitalization stocks may be more volatile than those of larger companies. Small capitalization and medium capitalization stocks may be traded over-the-counter. OTC stocks may trade less frequently and in smaller volume than exchange-listed stocks and may have more price volatility than that of exchange-listed stocks.
MULTI-ASSET CAPITAL STABILITY FUND - Class Y Prospectus | SIMT MULTI-ASSET CAPITAL STABILITY FUND | Currency Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]

Currency Risk — As a result of the Fund's investments in securities or other investments denominated in, and/or receiving revenues in, foreign currencies, the Fund will be subject to currency risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency hedged. In either event, the dollar value of an investment in the Fund would be adversely affected. Currency exchange rates may fluctuate in response to, among other things, changes in interest rates, intervention (or failure to intervene) by U.S. or foreign governments, central banks or supranational entities, or by the imposition of currency controls or other political developments in U.S. or abroad.