Label	Element	Value
Class A Prospectus \| SIMT Dynamic Asset Allocation Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SIMT Dynamic Asset Allocation Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Goal
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Long-term total return.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold Fund shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual Fund operating expenses or in the Example, affect the Fund's performance. For the fiscal period from July 31, 2015 to September 30, 2015, the Fund's annualized portfolio turnover rate was 2% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	2.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	EXAMPLE
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same.
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund employs a dynamic investment strategy seeking to achieve, over time, a total return in excess of the broad U.S. equity market by selecting investments from among a broad range of asset classes or market exposures based upon SEI Investments Management Corporation's (SIMC or the Adviser) expectations of risk and return. Asset classes or market exposures in which the Fund may invest include U.S. and foreign equities and bonds, currencies, and investment exposures to various market characteristics such as interest rates or volatility. The Fund's sub-adviser (the Sub-Adviser) selects the Fund's securities under the general supervision of SIMC. Assets of the Fund not allocated to the Sub-Adviser are managed directly by SIMC. The asset classes and market exposures used, and the Fund's allocations among them, are determined based on SIMC's views of fundamental, technical or valuation measures and may be dynamically adjusted (i.e. actively adjusted over long or short periods of time). The Fund may at any particular point in time be diversified across many exposures or concentrated in a limited number of exposures, including, possibly, a single asset class or market exposure. Although the Fund will seek to achieve excess total return through its dynamic investment selection, it will also normally maintain, as a primary component of its strategy, passive exposure to the large capitalization U.S. equity market. To the extent that the Fund is not dynamically invested in other asset classes or market exposures, the Fund's assets will generally be passively invested in a portfolio of securities designed to track, before fees and expenses, the performance of the large capitalization U.S. equity market. The Fund may obtain asset class or market exposures by investing directly (e.g., in equity and fixed income securities and other instruments) or indirectly (e.g., through the use of other pooled investment vehicles or derivative instruments, principally futures contracts, forward contracts, options and swaps). The particular types of securities and other instruments in which the Fund may invest are further described below. The Fund may invest in particular securities or instruments that are not specifically listed below, but which have similar characteristics or represent similar exposures as those described below. Equity Securities. The Fund may invest in equity securities, including common stocks, preferred stocks, convertible securities, warrants (including equity-linked warrants) and depositary receipts of U.S. and non-U.S. issuers (including emerging markets) of various market capitalizations and industries. Fixed Income Securities. The Fund may invest in fixed income securities that are investment or non-investment grade (also known as "junk bonds"), U.S.- or foreign-issued (including emerging markets), and corporate- or government-issued. The Fund's fixed income investments may include asset-backed securities, mortgage-backed securities, collateralized debt obligations (CDOs) and collateralized loan obligations (CLOs), corporate bonds and debentures, commercial paper, exchange traded notes (ETNs), money market instruments, mortgage dollar rolls, repurchase and reverse repurchase agreements, when issued/delayed delivery securities, zero coupon bonds, structured notes, construction loans, obligations of foreign governments, and obligations of either supranational entities issued or guaranteed by certain banks and entities organized to restructure the outstanding debt of such issuers. The Fund's fixed income investments may also include U.S. Treasury obligations, obligations issued by agencies or instrumentalities of the U.S. Government (including obligations not guaranteed by the U.S. Treasury), such as obligations issued by U.S. Government-sponsored entities, and Treasury Inflation Protected Securities (TIPS) and other inflation-linked debt securities of both U.S. and non-U.S. governments and corporations. The Fund may also invest a portion of its assets in bank loans, which are, generally, non-investment grade floating rate instruments, in the form of participations in the loans (participations) and assignments of all or a portion of the loans from third parties (assignments). The Fund may invest in fixed, variable and floating rate fixed income instruments. The Fund's portfolio and the Fund's investments in particular fixed income securities are not subject to any maturity or duration restrictions. Other Instruments. The Fund may also invest in real estate investment trusts (REITs) and securities issued by U.S. and non-U.S. real estate companies. Pooled Investment Vehicles. In addition to direct investment in securities and other instruments, the Fund may invest in affiliated and unaffiliated funds, including open-end funds, money market funds, closed-end funds and exchange-traded funds (ETFs), to obtain the Fund's desired exposure to a particular asset class. Derivative Instruments. The Fund may also purchase or sell futures contracts, forward contracts, options and swaps (including swaptions, caps, floors or collars) for return enhancement or hedging purposes or to obtain the Fund's desired exposure to a particular asset class or market exposure. Futures contracts, forward contracts and swaps may be used to synthetically obtain exposure to securities or baskets of securities and to manage the Fund's interest rate duration and yield curve exposure. These derivatives may also be used to mitigate the Fund's overall level of risk and/or the Fund's exposure to the risk of particular types of securities or market segments. The Fund may purchase or sell futures contracts (and options on futures contracts) on U.S. Government securities for return enhancement and hedging purposes. The Fund may purchase and sell forward contracts on currencies or securities for return enhancement and hedging purposes. Interest rate swaps are further used to manage the Fund's yield spread sensitivity. Swaps may be used for return enhancement or hedging purposes. Securities index and single security swaps may be used to manage the inflation-adjusted return of the Fund or to more efficiently gain exposure to a particular security or basket of securities. The Fund may buy credit default swaps in an attempt to manage credit risk where the Fund has credit exposure to an issuer, and the Fund may sell credit default swaps to more efficiently gain credit exposure to a security or basket of securities. The Fund may also, to a lesser extent, purchase or sell put or call options on securities, indexes or currencies for return enhancement or hedging purposes or to obtain the Fund's desired exposure to a particular asset class or market exposure. Currency Exposure. The Fund may invest in U.S. dollar and non-U.S. dollar denominated securities. SIMC or the Sub-Adviser(s) may also seek to enhance the Fund's return by actively managing the Fund's foreign currency exposure. In managing the Fund's currency exposure, SIMC or the Sub-Adviser(s) may buy and sell currencies (i.e., take long or short positions) using futures, options and foreign currency forward contracts. The Fund may take long and short positions in foreign currencies in excess of the value of the Fund's assets denominated in a particular currency or when the Fund does not own assets denominated in that currency. The Fund may also engage in currency transactions in an attempt to take advantage of certain inefficiencies in the currency exchange market, to increase its exposure to a foreign currency or to shift exposure to foreign currency fluctuations from one currency to another. In managing the Fund's currency exposure from foreign securities, SIMC or the Sub-Adviser(s) may buy and sell currencies for hedging or for speculative purposes. Short Sales. The Sub-Adviser may engage in short sales in an attempt to capitalize on equity securities that it or SIMC believes will underperform the market or their peers. When the Sub-Adviser sells securities short, it may invest the proceeds from the short sales in an attempt to enhance returns. This strategy may effectively result in the Fund having a leveraged investment portfolio, which results in greater potential for loss. Due to its investment strategy, the Fund may buy and sell securities and other instruments frequently.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	American Depositary Receipts (ADRs) Risk — ADRs are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. ADRs 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 and tax environments. 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. 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. Below Investment Grade Securities 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. These risks may be increased in foreign and emerging markets. Collateralized Debt Obligations (CDOs) and Collateralized Loan Obligations (CLOs) 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 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. 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. 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. 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. 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. 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 and liquidity risk are 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. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Credit risk is described above. 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. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation are not yet fully known and may not be for some time. New regulation of derivatives may make them more costly, may limit their availability or may otherwise adversely affect their value or performance. 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. Equity Market Risk — The risk that stock prices will fall over short or extended periods of time. Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value. 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. In the case of foreign securities, price fluctuations will reflect international economic and political events, as well as changes in currency valuations relative to the U.S. dollar. 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 and tax 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. Interest Rate Risk — The risk that a rise in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. 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. A low interest rate environment may present greater interest rate risk, because there may be a greater likelihood of rates increasing and rates may increase more rapidly. 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. 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. 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, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance. 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. 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. 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. Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and additional capital gains tax liabilities. 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. 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. 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. REITs 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. 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. Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund invests 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 or listed on an exchange. U.S. Government Securities Risk — 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. 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. Investing in the Fund involves risk, and there is no guarantee that the Fund will achieve its investment goal. You could lose money on your investment in the Fund, just as you could with other investments.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money on your investment in the Fund, just as you could with other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The Fund commenced operations on July 31, 2015. Because the Fund did not have a full calendar year of performance as of December 31, 2015, performance results have not been provided.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	The Fund commenced operations on July 31, 2015. Because the Fund did not have a full calendar year of performance as of December 31, 2015, performance results have not been provided.
Class A Prospectus \| SIMT Dynamic Asset Allocation Fund \| Class A
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.60%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.65%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.25%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 127
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	$ 397

Label

Element

Value

Class A Prospectus | SIMT Dynamic Asset Allocation Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

SIMT Dynamic Asset Allocation Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Long-term total return.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold Fund shares.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

PORTFOLIO TURNOVER

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual Fund operating expenses or in the Example, affect the Fund's performance. For the fiscal period from July 31, 2015 to September 30, 2015, the Fund's annualized portfolio turnover rate was 2% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

2.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

EXAMPLE

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund employs a dynamic investment strategy seeking to achieve, over time, a total return in excess of the broad U.S. equity market by selecting investments from among a broad range of asset classes or market exposures based upon SEI Investments Management Corporation's (SIMC or the Adviser) expectations of risk and return. Asset classes or market exposures in which the Fund may invest include U.S. and foreign equities and bonds, currencies, and investment exposures to various market characteristics such as interest rates or volatility. The Fund's sub-adviser (the Sub-Adviser) selects the Fund's securities under the general supervision of SIMC. Assets of the Fund not allocated to the Sub-Adviser are managed directly by SIMC.

The asset classes and market exposures used, and the Fund's allocations among them, are determined based on SIMC's views of fundamental, technical or valuation measures and may be dynamically adjusted (i.e. actively adjusted over long or short periods of time). The Fund may at any particular point in time be diversified across many exposures or concentrated in a limited number of exposures, including, possibly, a single asset class or market exposure.

Although the Fund will seek to achieve excess total return through its dynamic investment selection, it will also normally maintain, as a primary component of its strategy, passive exposure to the large capitalization U.S. equity market. To the extent that the Fund is not dynamically invested in other asset classes or market exposures, the Fund's assets will generally be passively invested in a portfolio of securities designed to track, before fees and expenses, the performance of the large capitalization U.S. equity market.

The Fund may obtain asset class or market exposures by investing directly (e.g., in equity and fixed income securities and other instruments) or indirectly (e.g., through the use of other pooled investment vehicles or derivative instruments, principally futures contracts, forward contracts, options and swaps). The particular types of securities and other instruments in which the Fund may invest are further described below. The Fund may invest in particular securities or instruments that are not specifically listed below, but which have similar characteristics or represent similar exposures as those described below.

Equity Securities. The Fund may invest in equity securities, including common stocks, preferred stocks, convertible securities, warrants (including equity-linked warrants) and depositary receipts of U.S. and non-U.S. issuers (including emerging markets) of various market capitalizations and industries.

Fixed Income Securities. The Fund may invest in fixed income securities that are investment or non-investment grade (also known as "junk bonds"), U.S.- or foreign-issued (including emerging markets), and corporate- or government-issued. The Fund's fixed income investments may include asset-backed securities, mortgage-backed securities, collateralized debt obligations (CDOs) and collateralized loan obligations (CLOs), corporate bonds and debentures, commercial paper, exchange traded notes (ETNs), money market instruments, mortgage dollar rolls, repurchase and reverse repurchase agreements, when issued/delayed delivery securities, zero coupon bonds, structured notes, construction loans, obligations of foreign governments, and obligations of either supranational entities issued or guaranteed by certain banks and entities organized to restructure the outstanding debt of such issuers.

The Fund's fixed income investments may also include U.S. Treasury obligations, obligations issued by agencies or instrumentalities of the U.S. Government (including obligations not guaranteed by the U.S. Treasury), such as obligations issued by U.S. Government-sponsored entities, and Treasury Inflation Protected Securities (TIPS) and other inflation-linked debt securities of both U.S. and non-U.S. governments and corporations.

The Fund may also invest a portion of its assets in bank loans, which are, generally, non-investment grade floating rate instruments, in the form of participations in the loans (participations) and assignments of all or a portion of the loans from third parties (assignments).

The Fund may invest in fixed, variable and floating rate fixed income instruments. The Fund's portfolio and the Fund's investments in particular fixed income securities are not subject to any maturity or duration restrictions.

Other Instruments. The Fund may also invest in real estate investment trusts (REITs) and securities issued by U.S. and non-U.S. real estate companies.

Pooled Investment Vehicles. In addition to direct investment in securities and other instruments, the Fund may invest in affiliated and unaffiliated funds, including open-end funds, money market funds, closed-end funds and exchange-traded funds (ETFs), to obtain the Fund's desired exposure to a particular asset class.

Derivative Instruments. The Fund may also purchase or sell futures contracts, forward contracts, options and swaps (including swaptions, caps, floors or collars) for return enhancement or hedging purposes or to obtain the Fund's desired exposure to a particular asset class or market exposure. Futures contracts, forward contracts and swaps may be used to synthetically obtain exposure to securities or baskets of securities and to manage the Fund's interest rate duration and yield curve exposure. These derivatives may also be used to mitigate the Fund's overall level of risk and/or the Fund's exposure to the risk of particular types of securities or market segments. The Fund may purchase or sell futures contracts (and options on futures contracts) on U.S. Government securities for return enhancement and hedging purposes. The Fund may purchase and sell forward contracts on currencies or securities for return enhancement and hedging purposes. Interest rate swaps are further used to manage the Fund's yield spread sensitivity.

Swaps may be used for return enhancement or hedging purposes. Securities index and single security swaps may be used to manage the inflation-adjusted return of the Fund or to more efficiently gain exposure to a particular security or basket of securities. The Fund may buy credit default swaps in an attempt to manage credit risk where the Fund has credit exposure to an issuer, and the Fund may sell credit default swaps to more efficiently gain credit exposure to a security or basket of securities. The Fund may also, to a lesser extent, purchase or sell put or call options on securities, indexes or currencies for return enhancement or hedging purposes or to obtain the Fund's desired exposure to a particular asset class or market exposure.

Currency Exposure. The Fund may invest in U.S. dollar and non-U.S. dollar denominated securities. SIMC or the Sub-Adviser(s) may also seek to enhance the Fund's return by actively managing the Fund's foreign currency exposure. In managing the Fund's currency exposure, SIMC or the Sub-Adviser(s) may buy and sell currencies (i.e., take long or short positions) using futures, options and foreign currency forward contracts. The Fund may take long and short positions in foreign currencies in excess of the value of the Fund's assets denominated in a particular currency or when the Fund does not own assets denominated in that currency. The Fund may also engage in currency transactions in an attempt to take advantage of certain inefficiencies in the currency exchange market, to increase its exposure to a foreign currency or to shift exposure to foreign currency fluctuations from one currency to another. In managing the Fund's currency exposure from foreign securities, SIMC or the Sub-Adviser(s) may buy and sell currencies for hedging or for speculative purposes.

Short Sales. The Sub-Adviser may engage in short sales in an attempt to capitalize on equity securities that it or SIMC believes will underperform the market or their peers. When the Sub-Adviser sells securities short, it may invest the proceeds from the short sales in an attempt to enhance returns. This strategy may effectively result in the Fund having a leveraged investment portfolio, which results in greater potential for loss.

Due to its investment strategy, the Fund may buy and sell securities and other instruments frequently.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

American Depositary Receipts (ADRs) Risk — ADRs are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and generally trade on an established market. ADRs 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 and tax environments.

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.

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.

Below Investment Grade Securities 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. These risks may be increased in foreign and emerging markets.

Collateralized Debt Obligations (CDOs) and Collateralized Loan Obligations (CLOs) 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 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.

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.

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.

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.

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.

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 and liquidity risk are 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. Valuation risk is the risk that the derivative may be difficult to value and/or valued incorrectly. Credit risk is described above. 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. Recent legislation calls for new regulation of the derivatives markets. The extent and impact of the regulation are not yet fully known and may not be for some time. New regulation of derivatives may make them more costly, may limit their availability or may otherwise adversely affect their value or performance.

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.

Equity Market Risk — The risk that stock prices will fall over short or extended periods of time.

Extension Risk — The risk that rising interest rates may extend the duration of a fixed income security, typically reducing the security's value.

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. In the case of foreign securities, price fluctuations will reflect international economic and political events, as well as changes in currency valuations relative to the U.S. dollar.

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 and tax 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.

Interest Rate Risk — The risk that a rise in interest rates will cause a fall in the value of fixed income securities, including U.S. Government securities, in which the Fund invests. 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. A low interest rate environment may present greater interest rate risk, because there may be a greater likelihood of rates increasing and rates may increase more rapidly.

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.

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.

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, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance.

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.

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.

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.

Portfolio Turnover Risk — Due to its investment strategy, the Fund may buy and sell securities frequently. This may result in higher transaction costs and additional capital gains tax liabilities.

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.

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.

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.

REITs 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.

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.

Small and Medium Capitalization Risk — The risk that small and medium capitalization companies in which the Fund invests 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 or listed on an exchange.

U.S. Government Securities Risk — 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. 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.

Investing in the Fund involves risk, and there is no guarantee that the Fund will achieve its investment goal. You could lose money on your investment in the Fund, just as you could with other investments.

Risk Lose Money [Text]

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You could lose money on your investment in the Fund, just as you could with other investments.

Bar Chart and Performance Table [Heading]

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Performance Information

Performance Narrative [Text Block]

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The Fund commenced operations on July 31, 2015. Because the Fund did not have a full calendar year of performance as of December 31, 2015, performance results have not been provided.

Performance One Year or Less [Text]

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The Fund commenced operations on July 31, 2015. Because the Fund did not have a full calendar year of performance as of December 31, 2015, performance results have not been provided.

Class A Prospectus | SIMT Dynamic Asset Allocation Fund | Class A

Risk/Return:

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Management Fees

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0.60%

Distribution (12b-1) Fees

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none

Other Expenses

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0.65%