Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Jan. 31, 2012
SIMT Multi-Strategy Alternative Fund (Prospectus Summary) | SIMT Multi-Strategy Alternative Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	MULTI-STRATEGY ALTERNATIVE FUND
Investment Objective, Heading	rr_ObjectiveHeading	Investment Goal
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The Fund allocates its assets among a variety of investment strategies to seek to generate an absolute return with reduced correlation to the stock and bond markets.
Expense, Heading	rr_ExpenseHeading	Fees and Expenses
Expense, Narrative	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold Fund shares.
Shareholder Fees, Caption	rr_ShareholderFeesCaption	SHAREHOLDER FEES (fees paid directly from your investment)
Operating Expenses, Caption	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	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. During the most recent fiscal year, the Fund's portfolio turnover rate was 25% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	25.00%
Expenses, Not Correlated to Ratio Due to Acquired Fund Fees	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Because the Fund incurred AFFE during the most recent fiscal year, the operating expenses in this fee table will not correlate to the expense ratio in the Fund's financial statements (or the "Financial Highlights" section in the prospectus) because the financial statements include only the direct operating expenses incurred by the Fund, not the indirect costs of investing in other investment companies.
Expense Example, Heading	rr_ExpenseExampleHeading	EXAMPLE
Expense Example, Narrative	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	rr_ExpenseExampleByYearCaption	Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Investment Strategy, Heading	rr_StrategyHeading	Principal Investment Strategies
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	The Fund employs a strategy intended to generate an absolute (i.e., positive) return in various market cycles with reduced correlation to the stock and bond markets. The Fund allocates its assets among a variety of investment strategies through the use of: (i) affiliated and unaffiliated funds, including open-end funds, closed-end funds and exchange traded funds (Underlying Funds); and/or (ii) one or more investment Sub-Advisers. In addition, SIMC may directly manage a portion of the Fund's portfolio. The Underlying Funds or Sub-Advisers that are employed may apply any of a variety of investment strategies, which may include: (i) directional or tactical strategies, such as long/short equity, long/short credit and global tactical asset allocation; (ii) event driven strategies, such as distressed securities, special situations and merger arbitrage; and (iii) arbitrage strategies, such as fixed income or interest rate arbitrage, convertible arbitrage, pairs trading and equity market neutral. The Fund will allocate its assets among Underlying Funds and/or Sub-Advisers based on SIMC's analysis of the investment strategy, historical performance and the potential for each strategy to perform independently of each other. By allocating its assets in this manner, the Fund will seek to reduce risk, lower volatility and achieve positive returns in various market cycles. Allocation of assets to any one Underlying Fund, Sub-Adviser or strategy will vary based on market conditions. By investing in an Underlying Fund, the Fund becomes a shareholder of that Underlying Fund. Underlying Funds and Sub-Advisers may invest in a broad range of asset classes, securities and other investments to achieve their designated investment strategies, which may include U.S., foreign and emerging markets securities, equity securities of all types and capitalization ranges, investment and non-investment grade fixed income securities of any duration or maturity issued by corporations or governments, commodities, currencies, warrants, depositary receipts, exchange traded notes and derivative instruments, principally equity options, futures contracts, options on futures contracts, forward contracts and swap agreements. In addition, the Fund may invest in cash, money market instruments and other short-term obligations to achieve its investment goal. The Fund currently allocates assets to one Sub-Adviser pursuant to SIMC's "manager-of-managers" model, and such Sub-Adviser manages a portion of the Fund's portfolio under the general supervision of SIMC. The Fund is intended to be only one component of an investor's broader investment program and is not designed to be a complete investment program. Investors who seek to add an alternative component to their overall investment program may wish to allocate a portion of their investment to the Fund.
Risk, Heading	rr_RiskHeading	Principal Risks
Risk, Narrative	rr_RiskNarrativeTextBlock	While the Fund seeks to achieve an absolute return with reduced correlation to stock and bond markets, it may not achieve positive returns over short or long term periods. Investment strategies that have historically been non-correlated or have demonstrated low correlations to one another or to stock and bond markets may become correlated at certain times and, as a result, may cease to function as anticipated over either short or long term periods. The success of the Fund's investment strategy depends both on SIMC's selection of the Underlying Funds and Sub-Advisers and allocating assets to such Underlying Funds and Sub-Advisers. SIMC, an Underlying Fund or a Sub-Adviser may be incorrect in assessing market trends, the value or growth capability of particular securities or asset classes. In addition, the methodology by which SIMC allocates the Fund's assets to the Underlying Funds and Sub-Advisers may not achieve desired results and may cause the Fund to lose money or underperform other comparable mutual funds. The Fund, Underlying Funds and Sub-Advisers may apply any of a variety of investment strategies and may invest in a broad range of asset classes, securities and other investments to achieve their designated investment strategies. The principal risks of using such investment strategies and making investments in such asset classes, securities and other investments are set forth below. Because an Underlying Fund's use of an investment strategy or investment in an asset class, security or other investment is subject to the same or similar risks as the Fund's use of such strategy or investment in such asset class, security or other investment, the term "the Fund" in the paragraphs below collectively refers to both the Fund and each Underlying Fund. 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 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. 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, and asset-backed securities may not have the benefit of any security interest in the related assets. Below Investment Grade Securities Risk - Fixed income securities rated below investment grade (junk bonds) involve greater risks of default or downgrade and are more volatile than investment grade securities because the prospect of repayment of principal and interest of many of these securities is speculative. 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. 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 its active positions in currencies, the Fund 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. 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. 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. 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. Equity Market Risk - The risk that stock prices will fall over short or extended periods of time. 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. Exchange-Traded Funds (ETFs) 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. Exchange-Traded Notes (ETNs) - 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 delisted by the listing exchange. 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 since political turmoil and rapid changes in economic conditions are more likely to occur in these countries. Interest Rate Risk - The risk that the value of fixed income securities, including U.S. Government securities, will fall due to rising interest rates. Investment Company 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 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. 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, sell other securities instead or forego an investment opportunity, any of which could have a negative effect on Fund management or performance. Mortgage-Backed Securities Risk - Mortgage-backed securities are affected by, among other things, interest rate changes and the possibility of prepayment of the underlying mortgage loans. Mortgage-backed securities are also subject to the risk that underlying borrowers will be unable to meet their obligations. 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. Portfolio Turnover Risk - Due to their investment strategies, the Fund and the Underlying Funds may buy and sell securities frequently. This may result in higher transaction costs and additional capital gains tax liabilities. 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.     Small and Medium Capitalization Companies Risk - The smaller 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 and medium capitalization stocks may be more volatile than those of larger companies. Small and medium capitalization stocks may be traded over-the-counter or listed on an exchange. 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. 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. Loss of money is a risk of investing in the Fund.
Risk, Lose Money	rr_RiskLoseMoney	Loss of money is a risk of investing in the Fund.
Risk, Nondiversified Status	rr_RiskNondiversifiedStatus	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.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance, Narrative	rr_PerformanceNarrativeTextBlock	The bar chart and the performance table below provide some indication of the risks of an investment in the Fund by comparing the Fund's performance with a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1-800-DIAL-SEI.
Performance, Information Illustrates Variability of Returns	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and the performance table below provide some indication of the risks of an investment in the Fund by comparing the Fund's performance with a broad measure of market performance.
Performance, Availability Phone Number	rr_PerformanceAvailabilityPhone	1-800-DIAL-SEI
Performance, Past Does Not Indicate Future	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart, Closing	rr_BarChartClosingTextBlock	Best Quarter:  1.11% (03/31/11) Worst Quarter: -4.20% (09/30/11)
Performance Table, Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for the periods ended December 31, 2011)
Performance Table, Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table, Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table, Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table, Closing	rr_PerformanceTableClosingTextBlock	Although the Fund's performance is benchmarked against the return of the BofA Merrill Lynch 3-Month U.S. Treasury Bill Index, an investment in the Fund is substantially different from an investment in U.S. Treasury bills. Among other things, Treasury bills are backed by the full faith and credit of the U.S. Government and have a fixed rate of return. Investors in Treasury bills do not risk losing their investment, whereas loss of money is a risk of investing in the Fund. Further, an investment in the Fund is expected to be substantially more volatile than an investment in Treasury bills because of the breadth and types of securities and other instruments in which the Fund may invest.
SIMT Multi-Strategy Alternative Fund (Prospectus Summary) | SIMT Multi-Strategy Alternative Fund | BofA Merrill Lynch 3-Month U.S. Treasury Bill Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	BofA Merrill Lynch 3-Month U.S. Treasury Bill Index
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	0.10%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	0.12%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 31, 2010
SIMT Multi-Strategy Alternative Fund (Prospectus Summary) | SIMT Multi-Strategy Alternative Fund | Class A
Risk Return [Abstract]	rr_RiskReturnAbstract
Redemption Fee (applies to a redemption, or series of redemptions, from a single identifiable source that, in the aggregate, exceeds $25 million within any thirty (30) day period)	rr_RedemptionFeeOverRedemption	(0.25%)
Management Fees	rr_ManagementFeesOverAssets	1.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Dividend and Interest Expense on Securities Sold Short	rr_Component1OtherExpensesOverAssets	0.01%
Remainder of Other Expenses	rr_Component2OtherExpensesOverAssets	0.62%
Total Other Expenses	rr_Component3OtherExpensesOverAssets	0.63%
Acquired Funds Fees and Expenses (AFFE)	rr_AcquiredFundFeesAndExpensesOverAssets	1.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	3.77%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	379
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	1,152
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,944
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	4,010
Annual Return 2011	rr_AnnualReturn2011	(2.77%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2011
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.11%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(4.20%)
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class A Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(2.77%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	(1.31%)
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 31, 2010
SIMT Multi-Strategy Alternative Fund (Prospectus Summary) | SIMT Multi-Strategy Alternative Fund | Class A | After Taxes on Distributions
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class A Return After Taxes on Distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(3.43%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	(1.89%)
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 31, 2010
SIMT Multi-Strategy Alternative Fund (Prospectus Summary) | SIMT Multi-Strategy Alternative Fund | Class A | After Taxes on Distributions and Sales
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class A Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.80%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	(1.40%)
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 31, 2010

[1] Because the Fund incurred AFFE during the most recent fiscal year, the operating expenses in this fee table will not correlate to the expense ratio in the Fund's financial statements (or the "Financial Highlights" section in the prospectus) because the financial statements include only the direct operating expenses incurred by the Fund, not the indirect costs of investing in other investment companies.