Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	May 01, 2012
Registrant Name	dei_EntityRegistrantName	Natixis Funds Trust II
Loomis Sayles Absolute Strategies Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Loomis Sayles Absolute Strategies Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Goal
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide an attractive absolute total return, complemented by prudent investment management designed to manage risks and protect investor capital.
Objective, Secondary [Text Block]	rr_ObjectiveSecondaryTextBlock	The secondary goal of the Fund is to achieve these returns with relatively low volatility.
Expense [Heading]	rr_ExpenseHeading	Fund Fees & Expenses
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Fund Complex. More information about these and other discounts is available from your financial professional and in the section "How Sales Charges Are Calculated" on page 70 of the Prospectus and on page 103 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees(fees paid directly from your investment)
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)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	April 30, 2013
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 for you if your 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 its most recently ended fiscal year, the Fund's portfolio turnover rate was 141% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	141.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Fund Complex.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	100,000
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 (except where indicated). The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	If shares are redeemed:
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	If shares are not redeemed:
Strategy [Heading]	rr_StrategyHeading	Investments, Risks and Performance Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund has an absolute return investment objective, which means that it is not managed relative to an index and that it attempts to achieve positive total returns over a full market cycle. The Fund intends to pursue its objective by utilizing a flexible investment approach that allocates investments across a global range of investment opportunities related to credit, currencies and interest rates, while employing risk management strategies to mitigate downside risk. The Fund may invest up to 100% of its total assets in below investment-grade fixed-income securities (also known as "junk bonds") and derivatives that have returns related to the returns on below investment-grade fixed-income securities, although it is expected that, under normal market conditions, the Fund's net exposure ( i.e. , long exposures obtained through direct investments in securities and in derivatives minus short exposures obtained through derivatives) to below investment-grade fixed-income assets generally will not exceed 50% of the Fund's total assets. Under normal market conditions, the Fund also may invest up to 50% of its total assets in investments denominated in non-U.S. currencies and related derivatives, including up to 20% in investments denominated in emerging market currencies and related derivatives. The Fund expects that its exposure to these asset classes will often be obtained substantially through the use of derivative instruments. The Fund defines an "emerging market currency" as a currency of a country that carries a sovereign debt quality rating that is rated below investment-grade by either Standard & Poor's Ratings Group ("S&P") or Moody's Investors Service, Inc. ("Moody's"), or is unrated by both S&P and Moody's. Currency positions that are intended to hedge the Fund's non-U.S. currency exposure ( i.e. , currency positions that are not made for investment purposes) will offset positions in the same currency that are made for investment purposes when calculating the limitation on investments in non-U.S. and emerging market currency investments because the Fund believes that hedging a currency position is likely to negate some or all of the currency risk associated with the original currency position. The Fund does not have limits on the duration of its portfolio, and the Fund's duration will change over time. In selecting investments for the Fund, the Adviser develops long-term portfolio themes driven by macro-economic indicators. These include secular global economic trends, demographic trends and labor supply, analysis of global capital flows and assessments of geopolitical factors. The Adviser then develops shorter-term portfolio strategies based on factors including, but not limited to, economic, credit and Federal Reserve cycles, and top-down sector valuations and bottom-up security valuations. The Adviser employs active risk management, with a focus on credit, interest rate and currency risks. Additionally, the portfolio managers will use risk management tools in constructing and optimizing the portfolio and seek to manage risk on an ongoing basis. The portfolio management team expects to actively evaluate each investment idea based upon its return potential, its level of risk and its fit within the team's overall macro strategy when deciding whether to buy or sell investments, with the goal of continually optimizing the Fund's portfolio. The Fund will pursue its investment goal by obtaining long investment exposures through direct cash investments and derivatives and short investment exposures substantially through derivatives. A "long" investment exposure is an investment that rises in value with a rise in the value of an asset, asset class or index and declines in value with a decline in the value of that asset, asset class or index. A "short" investment exposure is an investment that rises in value with a decline in the value of an asset, asset class or index and declines in value with a rise in the value of that asset, asset class or index. The Fund's long and short investment exposures may, at times, each reach 100% of the assets invested in the Fund (excluding instruments primarily used for duration management or yield curve management and short-term investments (such as cash and money market instruments)), although these exposures may be higher or lower at any given time. Fixed-Income Investments. In connection with its principal investment strategies, the Fund may invest in a broad range of U.S. and non-U.S. fixed-income securities, including, but not limited to, corporate bonds, municipal securities, U.S. and non-U.S. government securities (including their agencies, instrumentalities and sponsored entities), securities of supranational entities, emerging market securities, commercial and residential mortgage-backed securities, collateralized mortgage obligations, other mortgage-related securities (such as adjustable rate mortgage securities), asset-backed securities, bank loans, convertible bonds, Rule 144A securities, real estate investment trusts ("REITs"), zero-coupon securities, step coupon securities, pay-in-kind ("PIK") securities, inflation-linked bonds, variable and floating rate securities, private placements and commercial paper. Non-U.S. Currency Investments. Under normal market conditions, the Fund may engage in a broad range of transactions involving non-U.S. and emerging market currencies, including, but not limited to, purchasing and selling forward currency exchange contracts in non-U.S. or emerging market currencies, investing in non-U.S. currency futures contracts, investing in options on non-U.S. currencies and non-U.S. currency futures, investing in cross-currency instruments (such as swaps), investing directly in non-U.S. currencies and investing in securities denominated in non-U.S. currencies. The Fund may engage in non-U.S. currency transactions for investment or for hedging purposes. Derivative Investments. For investment and hedging purposes, the Fund may invest substantially in a broad range of derivatives instruments and sometimes the majority of its investment returns will derive from its derivative investments. These derivative instruments include, but are not limited to, futures contracts (such as treasury futures and index futures), forward contracts, options (such as options on futures contracts, options on securities, interest rate/bond options, currency options, options on swaps and over-the-counter ("OTC") options), warrants (such as non-U.S. currency warrants) and swap transactions (such as interest rate swaps, total return swaps and index swaps). In addition, the Fund may invest in credit derivative products that may be used to manage default risk and credit exposure. Examples of such products include, but are not limited to, credit default swap index products (such as LCDX, CMBX and ABX index products), single name credit default swaps, loan credit default swaps and asset-backed credit default swaps. The Fund may, at times, invest substantially all of its assets in derivatives and securities used to support its obligations under those derivatives. Derivative instruments (such as those listed above) can be used to acquire or to transfer the risk and returns of a security or other asset without buying or selling the security or asset. The Fund's strategy may be highly dependent on the use of derivatives, and to the extent that they become unavailable or unattractive the Fund may be unable to fully implement its investment strategy. The Fund is non-diversified, which means that it is not limited to a percentage of assets that it may invest in any one issuer. Because the Fund may invest in the securities of a limited number of issuers, an investment in the Fund may involve a higher degree of risk than would be present in a diversified portfolio. The Fund expects to engage in active and frequent trading of securities and other instruments. Effects of frequent trading may include high transaction costs, which may lower the Fund's return, and realization of greater short-term capital gains, distributions of which are taxable as ordinary income to taxable shareholders. Trading costs and tax effects associated with frequent trading may adversely affect the Fund"s performance. The percentage limitations set forth herein are not investment restrictions and the Fund may exceed these limits from time to time. In addition, when calculating these exposures, the Fund may use the market value, the notional value, an adjusted notional value or some other measure of the value of a derivative in order to reflect what the Adviser believes to be the most accurate assessment of the Fund's real economic exposure. The total notional value of the Fund's derivative instruments may significantly exceed the total value of the Fund's assets. Although the Fund seeks positive total returns over time, the Fund's investment returns may be volatile over short periods of time. The Fund may outperform the overall securities market during periods of flat or negative performance and may underperform during periods of strong market performance. There can be no assurance that the Fund's returns over time or during any period will be positive.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program. You may lose money by investing in the Fund. Agency Securities Risk: Agency securities are subject to fixed-income securities risk. Certain debt securities issued or guaranteed by agencies of the U.S. government are guaranteed as to the payment of principal and interest by the relevant entity but have not been backed by the full faith and credit of the U.S. government. Instead, they have been supported only by the discretionary authority of the U.S. government to purchase the agency's obligations. An event affecting the guaranteeing entity could adversely affect the payment of principal or interest or both on the security and, therefore, these types of securities should be considered to be riskier than U.S. government securities. Below Investment-Grade Fixed-Income Securities Risk: This is the risk that the Fund's investments in below investment-grade fixed-income securities, also known as "junk bonds," may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, credit risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is predominantly speculative for below investment-grade fixed-income securities. Credit/Counterparty Risk: Credit risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivatives or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risks with respect to the counterparties of its derivative transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee of an exchange clearing house, are not available in connection with over-the-counter ("OTC") derivative transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its direct counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains. Currency Risk: Fluctuations in the exchange rates between different currencies may negatively affect an investment. The Fund may be subject to currency risk because it may invest a significant portion of its assets in currency-related instruments and may invest in securities or other instruments denominated in, or receive revenues in, foreign currencies. The Adviser may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged. Derivatives Risk: Derivatives are subject to changes in the value of the underlying asset or indices on which such transactions are based. There is no guarantee that the use of derivatives will be effective or that suitable transactions will be available. Even a small investment in derivatives may give rise to leverage risk and can have a significant impact on the Fund's exposure to securities markets values, interest rates or currency exchange rates. It is possible that the Fund's liquid assets may be insufficient to support its obligations under its derivatives positions. The use of derivatives for other than hedging purposes may be considered a speculative activity, and involves greater risks than are involved in hedging. The use of derivatives may cause the Fund to incur losses greater than those which would have occurred had derivatives not been used. The Fund's use of derivatives, such as futures, forward contracts, options, warrants, foreign currency transactions, swaps and credit default swaps, involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for forward contracts, swaps and other OTC derivatives), the risk of difficulties in pricing and valuation, the risk that changes in the value of a derivative may not correlate perfectly with relevant assets, rates or indices, liquidity risk, allocation risk and the risk of losing more than the initial margin required to initiate derivatives positions. There is also the risk that the Fund may be unable to terminate or sell a derivatives position at an advantageous time or price. Moreover, a number of broker-dealers and other financial institutions have recently experienced extreme financial difficulty, sometimes resulting in bankruptcy of the institution. There can be no assurance that the Fund's derivative counterparties will be able to avoid experiencing similar financial difficulties, possibly resulting in losses to the Fund. Emerging Markets Risk: Investing in emerging markets companies, which may be smaller and have shorter operating histories than companies in developed markets, involves risks in addition to, and greater than, those generally associated with investing in companies in developed foreign markets. The extent of economic development, political stability, market depth, infrastructure, capitalization and regulatory oversight in emerging market economies is generally less than in more developed markets. Fixed-Income Securities Risk: Fixed-income securities are subject to credit risk, interest rate risk and liquidity risk. You may lose money on your investment due to unpredictable drops in a security's value or periods of below-average performance in a given security or in the securities market as a whole. In addition, an economic downturn or period of rising interest rates could adversely affect the market of these securities and reduce the Fund's ability to sell them. Foreign Securities Risk: Investments in foreign securities may be subject to greater political, economic, environmental, credit and information risks. The Fund's investments in foreign securities are subject to foreign currency fluctuations. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity. Inflation/Deflation Risk: Inflation risk is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases the present value of future payments. Deflation risk is the risk that prices throughout the economy decline over time (the opposite of inflation). Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund's portfolio. Because the Fund seeks positive returns that exceed the rate of inflation over time, if the portfolio managers' inflation forecasts are incorrect, the Fund may be more severely impacted than other funds. Interest Rate Risk: Changes in interest rates may cause the value of the Fund's investments to decrease. Generally, the value of fixed-income securities rises when prevailing interest rates fall and falls when interest rates rise. A period of low interest rates may cause the Fund to have a low or negative yield, potentially reducing the value of your investment. The value of zero-coupon and pay-in-kind ("PIK") bonds may be more sensitive to fluctuations in interest rates than other fixed-income securities. Rule 144A securities and structured notes may be more illiquid than other fixed-income securities. Issuer Risk: The value of the Fund's investments may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods and services. Leverage Risk: Use of derivative instruments may involve leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset price movements into larger changes in value. To the extent that the Fund uses a derivative for purposes other than as a hedge, or if the Fund hedges imperfectly, the Fund is directly exposed to the risks of that derivative and any loss generated by the derivative will not be offset by a gain. The use of leverage increases the impact of gains and losses on a fund's returns, and may lead to significant losses if investments are not successful. However, the Adviser will attempt to ensure that at all times the Fund has sufficient liquid assets to enable it to satisfy its obligations under its derivative contracts. Liquidity Risk: Liquidity risk exists when particular investments are difficult to purchase or sell, possibly preventing the Fund from selling these illiquid securities at an advantageous price or time. A lack of liquidity also may cause the value of investments to decline. Illiquid investments also may be difficult to value. Management Risk: A strategy used by the Fund's portfolio managers may fail to produce the intended result. Market Risk: The market value of a security will move up and down, sometimes rapidly and unpredictably, based upon a change in an issuer's financial condition, as well as overall market and economic conditions. The Fund's portfolio managers will attempt to reduce this risk by implementing various volatility management strategies and techniques. However, there is no guarantee that such strategies and techniques will produce the intended result. Mortgage-Related and Asset-Backed Securities Risk: In addition to the risks associated with investments in fixed-income securities generally (for example, credit, liquidity and valuation risk), mortgage-related and asset-backed securities are subject to the risks of the mortgages and assets underlying the securities as well as prepayment risk, the risk that the securities may be prepaid and result in the reinvestment of the prepaid amounts in securities with lower yields than the prepaid obligations. Conversely, there is a risk that an unexpected rise in interest rates will extend the life of a mortgage-related or asset-backed security beyond the expected prepayment time, typically reducing the security's value. The Fund also may incur a loss when there is a prepayment of securities that were purchased at a premium. The Fund's investments in other asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. Non-Diversification Risk: Compared with other mutual funds, the Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, the Fund may have more risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's NAV. Short Exposure Risk: A short exposure through a derivative may present various risks, including credit/counterparty risk and leverage risk. If the value of the asset, asset class or index on which the Fund has obtained a short investment exposure increases, the Fund will incur a loss. Unlike a direct cash investment like a stock, bond or exchange-traded fund, where the potential loss is limited to the purchase price, the potential risk of loss from a short exposure is theoretically unlimited. Moreover, there can be no assurance that securities necessary to cover a short position will be available for purchase.
Risk Lose Money [Text]	rr_RiskLoseMoney	You may lose money by investing in the Fund.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk: Compared with other mutual funds, the Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, the Fund may have more risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's NAV.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Risk/Return Bar Chart and Table
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table shown below provide some indication of the risks of investing in the Fund by showing the Fund's performance in the first full year and by showing how the Fund's average annual returns for the one-year and life-of-Fund periods compare to those of a broad measure of market performance. The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated performance information is available online at ngam.natixis.com and/or by calling the Fund toll-free at 800-225-5478. The chart does not reflect any sales charge that you may be required to pay when you buy or redeem the Fund’s shares. A sales charge will reduce your return.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table shown below provide some indication of the risks of investing in the Fund by showing the Fund's performance in the first full year and by showing how the Fund's average annual returns for the one-year and life-of-Fund periods compare to those of a broad measure of market performance. The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated performance information is available online at ngam.natixis.com and/or by calling the Fund toll-free at 800-225-5478.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-225-5478
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	ngam.natixis.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Total Returns for Class A Shares
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: First Quarter 2011, 1.33% Lowest Quarterly Return: Third Quarter 2011, -4.69%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for the periods ended December 31, 2011)
Index No Deduction for Fees, Expenses, Taxes [Text]	rr_IndexNoDeductionForFeesExpensesTaxes	Index performance reflects no deduction for fees, expenses, or taxes.
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	After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. The after–tax returns are shown for only one class of the Fund. After–tax returns for the other classes of the Fund will vary. Index performance reflects no deduction for fees, expenses, or taxes. The Return After Taxes on Distributions & Sale of Fund Shares for the one–year period and life-of-Fund period exceeds the Return Before Taxes due to an assumed benefit from losses on a sale of Fund shares at the end of the measurement period.
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. Actual after-tax returns depend on an investor’s 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, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. The after–tax returns are shown for only one class of the Fund. After–tax returns for the other classes of the Fund will vary. Index performance reflects no deduction for fees, expenses, or taxes. The Return After Taxes on Distributions & Sale of Fund Shares for the one–year period and life-of-Fund period exceeds the Return Before Taxes due to an assumed benefit from losses on a sale of Fund shares at the end of the measurement period.
Loomis Sayles Absolute Strategies Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.50%
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	none
Redemption fees	rr_RedemptionFeeOverRedemption	none
Management fees	rr_ManagementFeesOverAssets	0.70%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses-Fee/expense recovery	rr_Component1OtherExpensesOverAssets	none	[1]
Other expenses-Remainder of other expenses	rr_Component2OtherExpensesOverAssets	0.22%
Total other expenses	rr_OtherExpensesOverAssets	0.22%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.17%
Fee waiver and/or expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses after fee waiver and/or expense reimbursement	rr_NetExpensesOverAssets	1.17%
1 year	rr_ExpenseExampleYear01	564
3 years	rr_ExpenseExampleYear03	805
5 years	rr_ExpenseExampleYear05	1,065
10 years	rr_ExpenseExampleYear10	1,806
2011	rr_AnnualReturn2011	(3.90%)
Past 1 Year	rr_AverageAnnualReturnYear01	(8.20%)
Life of Fund	rr_AverageAnnualReturnSinceInception	(7.52%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2010
Loomis Sayles Absolute Strategies Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	1.00%
Redemption fees	rr_RedemptionFeeOverRedemption	none
Management fees	rr_ManagementFeesOverAssets	0.70%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses-Fee/expense recovery	rr_Component1OtherExpensesOverAssets	none	[1]
Other expenses-Remainder of other expenses	rr_Component2OtherExpensesOverAssets	0.21%
Total other expenses	rr_OtherExpensesOverAssets	0.21%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.91%
Fee waiver and/or expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses after fee waiver and/or expense reimbursement	rr_NetExpensesOverAssets	1.91%
1 year	rr_ExpenseExampleYear01	294
3 years	rr_ExpenseExampleYear03	600
5 years	rr_ExpenseExampleYear05	1,032
10 years	rr_ExpenseExampleYear10	2,233
1 year	rr_ExpenseExampleNoRedemptionYear01	194
3 years	rr_ExpenseExampleNoRedemptionYear03	600
5 years	rr_ExpenseExampleNoRedemptionYear05	1,032
10 years	rr_ExpenseExampleNoRedemptionYear10	2,233
Past 1 Year	rr_AverageAnnualReturnYear01	(5.62%)
Life of Fund	rr_AverageAnnualReturnSinceInception	(4.22%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2010
Loomis Sayles Absolute Strategies Fund | Class Y
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	rr_MaximumDeferredSalesChargeOverOther	none
Redemption fees	rr_RedemptionFeeOverRedemption	none
Management fees	rr_ManagementFeesOverAssets	0.70%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses-Fee/expense recovery	rr_Component1OtherExpensesOverAssets	none	[1]
Other expenses-Remainder of other expenses	rr_Component2OtherExpensesOverAssets	0.22%
Total other expenses	rr_OtherExpensesOverAssets	0.22%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.92%
Fee waiver and/or expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total annual fund operating expenses after fee waiver and/or expense reimbursement	rr_NetExpensesOverAssets	0.92%
1 year	rr_ExpenseExampleYear01	94
3 years	rr_ExpenseExampleYear03	293
5 years	rr_ExpenseExampleYear05	509
10 years	rr_ExpenseExampleYear10	1,131
Past 1 Year	rr_AverageAnnualReturnYear01	(3.78%)
Life of Fund	rr_AverageAnnualReturnSinceInception	(3.24%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2010
Return After Taxes on Distributions | Loomis Sayles Absolute Strategies Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Past 1 Year	rr_AverageAnnualReturnYear01	(9.20%)
Life of Fund	rr_AverageAnnualReturnSinceInception	(8.49%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2010
Return After Taxes on Distributions & Sale of Fund Shares | Loomis Sayles Absolute Strategies Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Past 1 Year	rr_AverageAnnualReturnYear01	(5.29%)
Life of Fund	rr_AverageAnnualReturnSinceInception	(6.92%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 15, 2010
3-month London Interbank Offered Rate (LIBOR) | Loomis Sayles Absolute Strategies Fund
Risk/Return:	rr_RiskReturnAbstract
Past 1 Year	rr_AverageAnnualReturnYear01	0.27%
Life of Fund	rr_AverageAnnualReturnSinceInception	0.27%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 01, 2011

[1] Loomis, Sayles & Company, L.P. ("Loomis Sayles" or the "Adviser") has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 1.30%, 2.05% and 1.05% of the Fund's average daily net assets for Class A, C and Y shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2013 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below 1.30%, 2.05% and 1.05% of the Fund's average daily net assets for Class A, C and Y shares, respectively. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.