Label

Element

Value

(CGM Advisor Targeted Equity Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term growth of capital through investment in equity securities of companies whose earnings are expected to grow at a faster rate than that of the overall United States economy.

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 $50,000 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 65 of the Prospectus and on page 118 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

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 $50,000 in the Natixis Fund Complex.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 50,000

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)

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 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:

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 229% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

229.00%

Strategy [Heading]

rr_StrategyHeading

Investments, Risks and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in equity investments, including common stocks and preferred stocks. The Fund will generally invest in a focused portfolio of common stocks of large-capitalization companies that the Fund's adviser, Capital Growth Management Limited Partnership ("CGM"), expects will grow at a faster rate than that of the overall United States economy. When CGM believes that market conditions warrant, however, CGM may select stocks based upon overall economic factors, such as the general economic outlook, the level and direction of interest rates and potential impact of inflation. The Fund will not invest in small-capitalization companies. In general, CGM seeks companies with the following characteristics, although not all of the companies selected will have these attributes:

• Well-established, with records of above-average growth

• Promise of maintaining their leadership positions in their respective industries

• Likely to benefit from internal revitalization or innovations, changes in consumer demand or basic economic forces

Rather than following a particular style, CGM employs a flexible approach and seeks to take advantage of opportunities as they arise. In making an investment decision, CGM generally employs the following methods:

• It uses a top-down approach, meaning that it analyzes the overall economic factors that may affect a potential investment.

• CGM then conducts a thorough analysis of certain industries and companies, evaluating the fundamentals of each on a case-by-case basis and focusing on companies that it determines are attractively valued.

• CGM's ultimate decision to purchase a security results from a thorough assessment of all of the information that CGM deems to be relevant at the time of investment.

• CGM will sell a stock if it determines that its investment expectations are not being met, if better opportunities are identified or if its price objective has been attained.

The Fund may also:

• Invest a significant portion of its assets in a single industry sector.

• Invest in foreign securities, including those in emerging markets.

• Invest in other investment companies, to the extent permitted by the Investment Company Act of 1940 (the "1940 Act").

• Invest in real estate investment trusts ("REITs").

• 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 returns, and realization of short-term capital gains, distributions of which are taxable to shareholders who are individuals as ordinary income. Trading costs and tax effects associated with frequent trading may adversely affect the Fund's performance.

Risk [Heading]

rr_RiskHeading

Principal Investment 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.

Emerging Markets Risk: In addition to the risks of investing in foreign investments generally, emerging markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, currency exchange restrictions, sanctions by the U.S. government and an issuer's unwillingness or inability to make principal or interest payments on its obligations. Emerging markets companies may be smaller and have shorter operating histories than companies in developed markets.

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. Growth stocks are generally more sensitive to market movements than other types of stocks primarily because their stock prices are based heavily on future expectations. If the adviser's assessment of the prospects for a company's growth is wrong, or if the adviser's judgment of how other investors will value the company's growth is wrong, then the price of the company's stock may fall or not approach the value that the adviser has placed on it. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock.

Focused Investment Risk: Because the Fund may invest in a small number of industries or securities, it may have more risk because the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's net asset value.

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 also are subject to foreign currency fluctuations and other foreign currency-related risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

Investments in Other Investment Companies Risk: The Fund will indirectly bear the management, service and other fees of any other investment companies, including ETFs, in which it invests in addition to its own expenses.

Key Personnel Risk: If one or more key individuals become unavailable to the investment adviser, including the Fund's portfolio manager, who is important to the management of the Fund's assets, the Fund could suffer material adverse effects, including substantial share redemptions that could require the Fund to sell portfolio securities at times when markets are not favorable.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Liquidity issues may also make it difficult to value the Fund's investments.

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 or portfolio 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.

REITs Risk: Investments in the real estate industry, including REITs, are particularly sensitive to economic downturns and are sensitive to factors such as changes in real estate values, property taxes and tax laws, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents and the management skill and creditworthiness of the issuer. Companies in the real estate industry also may be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or mortgage loans held by the REIT. REITs are also subject to default and prepayment risk. Many REITs are highly leveraged, increasing their risk. The Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund.

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

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 changes in the Fund's performance from year-to-year and by showing how the Fund's average annual returns for the one-year, five-year and ten-year 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.

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class A Shares

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

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.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return:
Fourth Quarter 2011, 15.77%

Lowest Quarterly Return:
Third Quarter 2011, -24.23%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns (for the periods ended December 31, 2014)

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

Class B total returns in the table below do not reflect the automatic conversion of Class B shares to Class A shares after eight years.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

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-advantaged 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. The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from losses on a sale of Fund shares at the end of the measurement period. Index performance reflects no deduction for fees, expenses or taxes.

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-advantaged arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from losses on a sale of Fund shares at the end of the measurement period.

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.

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 changes in the Fund's performance from year-to-year and by showing how the Fund's average annual returns for the one-year, five-year and ten-year periods compare to those of a broad measure of market performance.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown for only one class of the Fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

ngam.natixis.com

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-225-5478

(CGM Advisor Targeted Equity Fund) | S&P 500® Index

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

13.69%

Past 5 Years

rr_AverageAnnualReturnYear05

15.45%

Past 10 Years

rr_AverageAnnualReturnYear10

7.67%

(CGM Advisor Targeted Equity Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.71%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.19%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.15%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

685

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

919

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,172

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,892

Annual Return 2005

rr_AnnualReturn2005

13.19%

Annual Return 2006

rr_AnnualReturn2006

8.52%

Annual Return 2007

rr_AnnualReturn2007

34.42%

Annual Return 2008

rr_AnnualReturn2008

(38.36%)

Annual Return 2009

rr_AnnualReturn2009

25.19%

Annual Return 2010

rr_AnnualReturn2010

17.14%

Annual Return 2011

rr_AnnualReturn2011

(15.36%)

Annual Return 2012

rr_AnnualReturn2012

15.44%

Annual Return 2013

rr_AnnualReturn2013

29.01%

Annual Return 2014

rr_AnnualReturn2014

8.27%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarterly Return:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

15.77%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Dec. 31, 2011

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return:

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(24.23%)

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Past 1 Year

rr_AverageAnnualReturnYear01

2.04%

Past 5 Years

rr_AverageAnnualReturnYear05

8.55%

Past 10 Years

rr_AverageAnnualReturnYear10

6.74%

(CGM Advisor Targeted Equity Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

(2.78%)

Past 5 Years

rr_AverageAnnualReturnYear05

6.38%

Past 10 Years

rr_AverageAnnualReturnYear10

5.21%

(CGM Advisor Targeted Equity Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

2.29%

Past 5 Years

rr_AverageAnnualReturnYear05

6.15%

Past 10 Years

rr_AverageAnnualReturnYear10

5.05%

(CGM Advisor Targeted Equity Fund) | Class B

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

5.00%

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.71%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.18%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.89%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

692

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

894

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,221

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,019

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

192

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

594

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,021

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,019

Past 1 Year

rr_AverageAnnualReturnYear01

2.94%

Past 5 Years

rr_AverageAnnualReturnYear05

8.73%

Past 10 Years

rr_AverageAnnualReturnYear10

6.59%

(CGM Advisor Targeted Equity 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.71%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.19%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.90%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

293

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

597

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,026

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,222

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

193

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

597

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,026

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,222

Past 1 Year

rr_AverageAnnualReturnYear01

6.52%

Past 5 Years

rr_AverageAnnualReturnYear05

9.00%

Past 10 Years

rr_AverageAnnualReturnYear10

6.58%

(CGM Advisor Targeted Equity 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.71%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.18%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.89%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

91

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

284

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

493

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,096

Past 1 Year

rr_AverageAnnualReturnYear01

8.52%

Past 5 Years

rr_AverageAnnualReturnYear05

10.09%

Past 10 Years

rr_AverageAnnualReturnYear10

7.65%

(Natixis Diversified Income Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks current income with a secondary objective of capital appreciation.

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 65 of the Prospectus and on page 118 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

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

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, 2016

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 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:

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 41% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

41.00%

Strategy [Heading]

rr_StrategyHeading

Investments, Risks and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is designed to offer investors access to a diversified portfolio of complementary income-producing investment disciplines from specialized money managers through investment in a single mutual fund. The Fund's disciplines focus on income-producing fixed-income and equity securities. Each discipline is listed below.

Adviser/Subadviser andInvestment Discipline	Focus of Discipline	TargetAllocation		Minimum Allocation		Maximum Allocation
AEW Diversified REIT	U.S. Equity Real Estate Investment Trusts ("REITs")	25.00	%	20.00	%	30.00	%
Active Dividend Equity *	Dividend-paying common stocks of U.S. issuers	20.00	%	15.00	%	25.00	%
Loomis Sayles Inflation Protected Securities	Inflation protected securities, with an emphasis on U.S. Treasury Inflation Protected Securities ("TIPS")	15.00	%	10.00	%	20.00	%
Loomis Sayles Multi-Sector Bond	Investment grade fixed-income securities	40.00	%	30.00	%	50.00	%
*       This discipline is managed by NGAM Advisors, L.P. ("NGAM Advisors") through its division Active Investment Advisors ("Active").

Subject to the allocation policy adopted by the Fund's Board of Trustees, NGAM Advisors generally allocates capital invested in the Fund among its four disciplines according to the target allocations noted above. NGAM Advisors (with respect to the Active Dividend Equity discipline) and each of the subadvisers manages the portion of the Fund's assets allocated to them in accordance with Active's or the respective subadviser's distinct investment style and strategy. NGAM Advisors monitors the relative sizes of the disciplines on a monthly basis. When a discipline's percentage of the Fund exceeds the maximum or minimum allocation set forth in the table above, NGAM Advisors will generally reallocate capital away from or towards one or more disciplines in order to bring the discipline back within its target allocation range. Subject to approval by the Fund's Board of Trustees, NGAM Advisors may revise the Fund's target allocations from time to time. In addition, target allocations will vary and may not always be met.

The Fund may:

• Invest in equity securities, including common stocks and preferred stocks.

• Invest a significant portion of its assets in REITs and companies in the real-estate industry.

• Invest in securities offered in initial public offerings ("IPOs") and securities issued pursuant to Rule 144A under the Securities Act of 1933 ("Rule 144A securities").

• Invest in convertible preferred stock and convertible debt securities.

• Engage in options for hedging and investment purposes and enter into futures transactions, swap contracts (including credit default swaps), currency hedging transactions and other derivatives.

• Invest in fixed-income securities of any maturity, including those of foreign issuers and below investment-grade fixed-income securities (commonly known as "junk bonds").

• Invest in mortgage-related and asset-backed securities (including mortgage dollar rolls).

Risk [Heading]

rr_RiskHeading

Principal Investment 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.

Allocation Risk: The Fund's investment performance depends on how its assets are allocated. The allocation, as set forth above, may not be optimal in every market condition. You could lose money on your investment in the Fund as a result of this allocation.

Credit 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 OTC options. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including options, foreign currency transactions, futures transactions and swap transactions) are subject to changes in the value of the underlying assets or indices on which such instruments 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 that would have occurred had derivatives not been used. The Fund's use of derivatives involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for forward currency contracts, swaps and other over-the-counter ("OTC") traded derivatives), the risk of difficulties in pricing and valuation, the risk that changes in the value of a derivative may not correlate as expected with changes in the value of 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. The Fund's derivative counterparties may experience financial difficulties or otherwise be unwilling or unable to honor their obligations, possibly resulting in losses to the Fund.

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. Securities issued in IPOs tend to involve greater market risk than other equity securities due, in part, to public perception and the lack of publicly available information and trading history. Rule 144A securities may be less liquid than other equity securities. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock.

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.

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 also are subject to foreign currency fluctuations and other foreign currency-related risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

Inflation-Linked Securities Risk: Unlike conventional bonds, the principal or interest of inflation-linked securities such as TIPS is adjusted periodically to a specified rate of inflation (e.g., Consumer Price Index for all Urban Consumers). There can be no assurance that the inflation index will accurately measure the real rate of inflation. These securities may lose value in the event that the actual rate of inflation is different than the rate of inflation index.

Interest Rate Risk: Interest rate risk is the risk that the value of the Fund's investments will fall if interest rates rise. Generally, the value of fixed-income securities rises when prevailing interest rates fall and falls when interest rates rise. Interest rate risk generally is greater for funds that invest in fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations. 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, negatively impacting the performance of the Fund.

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. 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.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Decreases in the number of financial institutions willing to make markets in the Funds' investments or in their capacity or willingness to transact may increase the Funds' exposure to this risk. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Securities acquired in a private placement, such as Rule 144A securities, are generally subject to greater liquidity risk because they are subject to strict restrictions on resale and there may be no liquid secondary market or ready purchaser for such securities. Non-exchange traded derivatives are generally subject to greater liquidity risk as well. Liquidity issues may also make it difficult to value the Fund's investments.

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 or portfolio 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.

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.

REITs Risk: Investments in the real estate industry, including REITs, are particularly sensitive to economic downturns and are sensitive to factors such as changes in real estate values, property taxes and tax laws, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents and the management skill and creditworthiness of the issuer. Companies in the real estate industry also may be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or mortgage loans held by the REIT. REITs are also subject to default and prepayment risk. Many REITs are highly leveraged, increasing their risk. The Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund.

Small- and Mid-Capitalization Companies Risk: Compared to large-capitalization companies, small- and mid-capitalization companies are more likely to have limited product lines, markets or financial resources. Stocks of these companies often trade less frequently and in limited volume and their prices may fluctuate more than stocks of large-cap companies. As a result, it may be relatively more difficult for the Fund to buy and sell securities of small- and mid-cap companies.

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

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 changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the one-year, five-year and life-of-class periods compare to those of two broad measures of market performance. The Blended Index is an unmanaged, blended index composed of the following weights: 40% Barclays U.S. Aggregate Bond Index, 25% MSCI US REIT Index, 20% Dow Jones U.S. Select Dividend Index, and 15% Barclays U.S. TIPS Index. The four indices composing the Blended Index measure, respectively, the performance of investment-grade fixed-income securities, equity REIT securities, dividend-yielding equity securities, and Treasury inflation-protected securities. 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.

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class A Shares

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

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.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return:
Second Quarter 2009, 18.28%

Lowest Quarterly Return:
Fourth Quarter 2008, -18.23%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns (for the periods ended December 31, 2014)

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

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-advantaged 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.

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

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-advantaged arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans or individual retirement accounts.

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.

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 changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the one-year, five-year and life-of-class periods compare to those of two broad measures of market performance.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown for only one class of the Fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

ngam.natixis.com

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-225-5478

(Natixis Diversified Income Fund) | Barclays U.S. Aggregate Bond Index

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

5.97%

Past 5 Years

rr_AverageAnnualReturnYear05

4.45%

Life of Fund

rr_AverageAnnualReturnSinceInception

5.00%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 17, 2005

(Natixis Diversified Income Fund) | Blended Index

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

13.34%

Past 5 Years

rr_AverageAnnualReturnYear05

10.21%

Life of Fund

rr_AverageAnnualReturnSinceInception

6.92%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 17, 2005

(Natixis Diversified Income Fund) | Barclays U.S. Aggregate Bond Index (12/3/12)

Risk/Return:

rr_RiskReturnAbstract

Life of Fund

rr_AverageAnnualReturnSinceInception

1.77%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 03, 2012

(Natixis Diversified Income Fund) | Blended Index (12/3/12)

Risk/Return:

rr_RiskReturnAbstract

Life of Fund

rr_AverageAnnualReturnSinceInception

8.59%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 03, 2012

(Natixis Diversified Income 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

^[1]

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.55%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.26%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.06%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[2]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.06%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

553

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

772

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,008

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,686

Annual Return 2006

rr_AnnualReturn2006

14.24%

Annual Return 2007

rr_AnnualReturn2007

(2.80%)

Annual Return 2008

rr_AnnualReturn2008

(25.26%)

Annual Return 2009

rr_AnnualReturn2009

33.32%

Annual Return 2010

rr_AnnualReturn2010

16.73%

Annual Return 2011

rr_AnnualReturn2011

7.21%

Annual Return 2012

rr_AnnualReturn2012

13.22%

Annual Return 2013

rr_AnnualReturn2013

5.84%

Annual Return 2014

rr_AnnualReturn2014

13.08%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarterly Return:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.28%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return:

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(18.23%)

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Past 1 Year

rr_AverageAnnualReturnYear01

7.96%

Past 5 Years

rr_AverageAnnualReturnYear05

10.13%

Life of Fund

rr_AverageAnnualReturnSinceInception

6.74%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 17, 2005

(Natixis Diversified Income Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

6.95%

Past 5 Years

rr_AverageAnnualReturnYear05

9.10%

Life of Fund

rr_AverageAnnualReturnSinceInception

5.51%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 17, 2005

(Natixis Diversified Income Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

4.69%

Past 5 Years

rr_AverageAnnualReturnYear05

7.65%

Life of Fund

rr_AverageAnnualReturnSinceInception

4.87%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 17, 2005

(Natixis Diversified Income 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.55%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.26%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.81%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[2]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.81%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

284

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

569

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

980

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,127

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

184

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

569

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

980

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,127

Past 1 Year

rr_AverageAnnualReturnYear01

11.28%

Past 5 Years

rr_AverageAnnualReturnYear05

10.31%

Life of Fund

rr_AverageAnnualReturnSinceInception

6.47%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 17, 2005

(Natixis Diversified Income 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.55%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.27%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.82%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[2]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

0.82%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

84

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

262

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

455

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,014

Past 1 Year

rr_AverageAnnualReturnYear01

13.05%

Past 5 Years

rr_AverageAnnualReturnYear05

11.16%

^[3]

Life of Fund

rr_AverageAnnualReturnSinceInception

9.78%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 03, 2012

(Natixis Oakmark International Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

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 $50,000 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 65 of the Prospectus and on page 118 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

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 $50,000 in the Natixis Fund Complex.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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, 2016

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

Other expenses have been restated to reflect current custodian and transfer agency fees for the Fund effective October 1, 2014.

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:

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 31% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

31.00%

Strategy [Heading]

rr_StrategyHeading

Investments, Risks and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund invests primarily in a diversified portfolio of common stocks of non-U.S. companies. The Fund may invest in non-U.S. markets throughout the world, including emerging markets. Ordinarily, the Fund will invest in the securities of at least five countries outside the U.S. There are no geographic limits on the Fund's non-U.S. investments. Although the Fund invests primarily in common stocks of non-U.S. companies it may also invest in the securities of U.S. companies. The Fund may invest in the securities of small-, mid- and large-capitalization companies.

The Fund's subadviser, Harris Associates L.P. ("Harris Associates"), uses a value investment philosophy in selecting equity securities, such as common stocks, preferred stocks, warrants, and securities convertible into common stocks and preferred stocks. This investment philosophy is based upon the belief that, over time, a company's stock price converges with Harris Associates' estimate of its intrinsic or true business value. By "true business value," Harris Associates means its estimate of the price a knowledgeable buyer would pay to acquire the entire business. Harris Associates believes that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objective.

Harris Associates uses this value philosophy to identify companies that it believes have discounted stock prices compared to the companies' true business values. In assessing such companies, Harris Associates looks for the following characteristics, although not all of the companies selected will have these attributes: (1) free cash flows and intelligent investment of excess cash; (2) earnings that are growing and are reasonably predictable; and (3) high level of manager ownership.

Once Harris Associates determines that a security is selling at what it believes to be a significant discount and that the issuer has the additional qualities mentioned above, Harris Associates generally will consider buying that security for the Fund. Harris Associates usually sells a security when the price approaches its estimated worth or the issuer's fundamentals change. Harris Associates monitors each holding and adjusts its price targets as warranted to reflect changes in the issuer's fundamentals. The Fund's portfolio typically holds 30 to 65 stocks.

Risk [Heading]

rr_RiskHeading

Principal Investment 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.

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 in currency-related instruments and may invest in securities or other instruments deniminated in, or received revenues in, foreign currencies. The Fund may elect not to hedge currency risk, or may hedge such risk imperfectly, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

Emerging Markets Risk: In addition to the risks of investing in foreign investments generally, emerging markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, currency exchange restrictions, sanctions by the U.S. government and an issuer's unwillingness or inability to make principal or interest payments on its obligations. Emerging markets companies may be smaller and have shorter operating histories than companies in developed markets.

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. Value stocks can perform differently from the market as a whole and from other types of stocks. Value stocks also present the risk that their lower valuations fairly reflect their business prospects and that investors will not agree that the stocks represent favorable investment opportunities, and they may fall out of favor with investors and underperform growth stocks during any given period. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock. Small and mid-capitalization and emerging growth companies may be subject to more abrupt price movements, limited markets and less liquidity than larger, more established companies, which could adversely affect the value of the Fund's equity portfolio.

Focused Investment Risk: Because the Fund may invest in a small number of industries or securities, it may have more risk because the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's net asset value.

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 also are subject to foreign currency fluctuations and other foreign currency-related risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

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 or portfolio 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.

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

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 comparing the Fund's one-year and life-of-fund performance with 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.

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class A Shares

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

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.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return:
First Quarter 2012, 17.17%

Lowest Quarterly Return:
Third Quarter 2011, -20.47%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns (for the periods ended December 31, 2014)

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

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-advantaged 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 class of the Fund will vary. The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from the pass-through of foreign tax credits and from losses on a sale of Fund shares at the end of the measurement period. Index performance reflects no deduction for fees, expenses or taxes.

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-advantaged arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from the pass-through of foreign tax credits and from losses on a sale of Fund shares at the end of the measurement period.

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.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown for only one class of the Fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

ngam.natixis.com

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-225-5478

(Natixis Oakmark International Fund) | MSCI World ex USA Index (Net)

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

(4.32%)

Life of Fund

rr_AverageAnnualReturnSinceInception

4.62%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 15, 2010

(Natixis Oakmark International Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.85%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.20%

^[4]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.30%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[5]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.30%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

700

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

963

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,247

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,053

Annual Return 2011

rr_AnnualReturn2011

(14.55%)

Annual Return 2012

rr_AnnualReturn2012

28.78%

Annual Return 2013

rr_AnnualReturn2013

28.13%

Annual Return 2014

rr_AnnualReturn2014

(6.05%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarterly Return:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

17.17%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return:

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.47%)

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Past 1 Year

rr_AverageAnnualReturnYear01

(11.46%)

Life of Fund

rr_AverageAnnualReturnSinceInception

6.06%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 15, 2010

(Natixis Oakmark International Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

(12.12%)

Life of Fund

rr_AverageAnnualReturnSinceInception

5.75%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 15, 2010

(Natixis Oakmark International Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

(5.73%)

Life of Fund

rr_AverageAnnualReturnSinceInception

4.87%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 15, 2010

(Natixis Oakmark International 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.85%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.19%

^[4]

Total annual fund operating expenses

rr_ExpensesOverAssets

2.04%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[5]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

2.04%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

307

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

640

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,098

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,369

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

207

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

640

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,098

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,369

Past 1 Year

rr_AverageAnnualReturnYear01

(7.57%)

Life of Fund

rr_AverageAnnualReturnSinceInception

6.85%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 15, 2010

(Natixis U.S. Equity Opportunities Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term growth of capital.

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 $50,000 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 65 of the Prospectus and on page 118 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

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 $50,000 in the Natixis Fund Complex.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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, 2016

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

Other expenses have been restated to reflect current custodian and transfer agency fees for the Fund effective October 1, 2014.

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

The expense information shown in the table above includes acquired fund fees and expenses of less than 0.01%; the ratios may differ from the expense information disclosed in the Fund's financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.

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:

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 93% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

93.00%

Strategy [Heading]

rr_StrategyHeading

Investments, Risks and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund ordinarily invests at least 80% of its net assets (plus any borrowings made for investment purposes) in equity securities, including common stocks and preferred stocks. Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in securities of U.S. issuers. The Fund's approach to equity investing combines the styles of two subadvisers in selecting securities for each of the Fund's segments. The segments and their subadvisers are listed below.

• Harris Associates - Large Cap Value segment - Under normal circumstances, the Large Cap Value segment of the Fund managed by Harris Associates L.P. ("Harris Associates") will invest primarily in the common stocks of larger- capitalization companies that Harris Associates believes are trading at a substantial discount to the company's "true business value." By "true business value," Harris Associates means its estimate of the price a knowledgeable buyer would pay to acquire the entire business. Harris Associates believes that investing in securities priced significantly below their true business value presents the best opportunity to achieve the Fund's investment objectives. Harris Associates usually sells a security when the price approaches its estimated worth and monitors each holding and adjusts its price targets as warranted to reflect changes in the issuer's fundamentals.

• Loomis Sayles - All Cap Growth segment - Under normal circumstances, the All Cap Growth segment of the Fund, managed by Loomis, Sayles & Company, L.P. ("Loomis Sayles"), will invest primarily in equity securities, including common stocks, preferred stocks, convertible securities and warrants. This segment may invest in companies of any size. The segment normally invests across a wide range of sectors and industries. The segment's portfolio manager employs a growth style of equity management that emphasizes companies with sustainable competitive advantages, long-term secular growth and profitable cash flow returns and management teams focused on creating long-term value for shareholders. The segment's portfolio manager aims to invest in companies when they trade at a significant discount to the estimate of intrinsic value. The segment will consider selling a portfolio investment when the portfolio manager believes an unfavorable structural change occurs within a given business or the markets in which it operates, a critical underlying investment assumption is flawed, when a more attractive reward-to-risk opportunity becomes available, when the portfolio manager believes the current price fully reflects intrinsic value, or for other investment reasons which the portfolio manager deems appropriate.

Subject to the allocation policy adopted by the Fund's Board of Trustees, NGAM Advisors, L.P. ("NGAM Advisors") generally allocates capital invested in the Fund equally (i.e., 50%) between its two segments. Under the allocation policy, NGAM Advisors may also allocate capital away from or towards each segment from time to time and may reallocate capital between the segments. Each subadviser manages its segment of the Fund's assets in accordance with its distinct investment style and strategy.

The Fund may also:

• Invest in securities offered in initial public offerings ("IPOs") and securities issued pursuant to Rule 144A under the Securities Act of 1933 ("Rule 144A securities").

• Invest in convertible preferred stock and convertible debt securities.

• Invest in real estate investment trusts ("REITs").

• Invest in fixed-income securities, including U.S. government bonds and below-investment grade fixed-income securities (commonly known as "junk bonds").

• Hold securities of foreign issuers traded over-the-counter or on foreign exchanges, including securities in emerging markets and related currency hedging transactions.

• Invest in equity securities of Canadian issuers.

Risk [Heading]

rr_RiskHeading

Principal Investment 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.

Allocation Risk: The Fund's investment performance depends on how its assets are allocated. The allocation, as set forth above, may not be optimal in every market condition. You could lose money on your investment in the Fund as a result of this allocation.

Credit 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.

Emerging Markets Risk: In addition to the risks of investing in foreign investments generally, emerging markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, currency exchange restrictions, sanctions by the U.S. government and an issuer's unwillingness or inability to make principal or interest payments on its obligations. Emerging markets companies may be smaller and have shorter operating histories than companies in developed markets.

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. Securities issued in IPOs tend to involve greater market risk than other equity securities due, in part, to public perception and the lack of publicly available information and trading history. Rule 144A securities may be less liquid than other equity securities. Growth stocks are generally more sensitive to market movements than other types of stocks primarily because their stock prices are based heavily on future expectations. In the subadviser's assessment of the prospects for a company's growth is wrong, or if the subadviser's judgment of how other investors will value the company's growth is wrong, then the price of the company's stock may fall or not approach the value that the subadviser has placed on it. Value stocks can perform differently from the market as a whole and from other types of stocks. Value stocks also present the risk that their lower valuations fairly reflect their business prospects and that investors will not agree that the stocks represent favorable investment opportunities, and they may fall out of favor with investors and underperform growth stocks during any given period. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock.

Fixed-Income Securities Risk: Fixed-income securities are subject to credit risk, interest rate risk and liquidity risk. Generally, the value of fixed-income securities rises when prevailing interest rates fall and falls when interest rates rise. 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. Below investment-grade fixed-income securities may be subject to these risks (including the risk of default) to a greater extent than other fixed-income securities. 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 also are subject to foreign currency fluctuations and other foreign currency-related risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Decreases in the number of financial institutions willing to make markets in the Funds' investments or in their capacity or willingness to transact may increase the Funds' exposure to this risk. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Securities acquired in a private placement, such as Rule 144A securities, are generally subject to greater liquidity risk because they are subject to strict restrictions on resale and there may be no liquid secondary market or ready purchaser for such securities. Non-exchange traded derivatives are generally subject to greater liquidity risk as well. Liquidity issues may also make it difficult to value the Fund's investments.

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 or portfolio 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.

REITs Risk: Investments in the real estate industry, including REITs, are particularly sensitive to economic downturns and are sensitive to factors such as changes in real estate values, property taxes and tax laws, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents and the management skill and creditworthiness of the issuer. Companies in the real estate industry also may be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or mortgage loans held by the REIT. REITs are also subject to default and prepayment risk. Many REITs are highly leveraged, increasing their risk. The Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund.

Small- and Mid-Capitalization Companies Risk: Compared to large-capitalization companies, small- and mid-capitalization companies are more likely to have limited product lines, markets or financial resources. Stocks of these companies often trade less frequently and in limited volume and their prices may fluctuate more than stocks of large-cap companies. As a result, it may be relatively more difficult for the Fund to buy and sell securities of small- and mid-cap companies.

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Risk/Return Bar Chart and Table

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year-to-year and by showing how the Fund's average annual returns for the one-year, five-year, and ten-year periods compare to those of two broad measures of market performance. The Russell 1000® Index is an unmanaged index that measures the performance of the large-cap segment of the U.S. equity universe. A subset of the Russell 3000® Index, it includes approximately 1,000 of the largest stocks based on a combination of market capitalization and current index membership. 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.

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class A Shares

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

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.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return:
Third Quarter 2009, 17.80%

Lowest Quarterly Return:
Fourth Quarter 2008, -24.20%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns (for the periods ended December 31, 2014)

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

Class B total returns in the table below do not reflect the automatic conversion of Class B shares to Class A shares after eight years.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

The Fund uses multiple subadvisers. The performance results shown above reflect results achieved by previous subadvisers using different investment strategies.

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-advantaged 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. The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from losses on a sale of Fund shares at the end of the measurement period. Index performance reflects no deduction for fees, expenses or taxes.

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-advantaged arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from losses on a sale of Fund shares at the end of the measurement period.

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.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year-to-year and by showing how the Fund's average annual returns for the one-year, five-year, and ten-year periods compare to those of two broad measures of market performance.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown for only one class of the Fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

ngam.natixis.com

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-225-5478

(Natixis U.S. Equity Opportunities Fund) | S&P 500® Index

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

13.69%

Past 5 Years

rr_AverageAnnualReturnYear05

15.45%

Past 10 Years

rr_AverageAnnualReturnYear10

7.67%

(Natixis U.S. Equity Opportunities Fund) | Russell 1000® Index

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

13.24%

Past 5 Years

rr_AverageAnnualReturnYear05

15.64%

Past 10 Years

rr_AverageAnnualReturnYear10

7.96%

(Natixis U.S. Equity Opportunities Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.80%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.26%

^[4],[6]

Fee/expense recovery

rr_Component1OtherExpensesOverAssets

0.02%

Remainder of other expenses

rr_Component2OtherExpensesOverAssets

0.24%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.31%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.31%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

701

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

966

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,252

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,063

Annual Return 2005

rr_AnnualReturn2005

7.57%

Annual Return 2006

rr_AnnualReturn2006

13.68%

Annual Return 2007

rr_AnnualReturn2007

13.69%

Annual Return 2008

rr_AnnualReturn2008

(40.05%)

Annual Return 2009

rr_AnnualReturn2009

36.41%

Annual Return 2010

rr_AnnualReturn2010

21.90%

Annual Return 2011

rr_AnnualReturn2011

(2.79%)

Annual Return 2012

rr_AnnualReturn2012

17.79%

Annual Return 2013

rr_AnnualReturn2013

35.75%

Annual Return 2014

rr_AnnualReturn2014

12.94%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarterly Return:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

17.80%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return:

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(24.20%)

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Past 1 Year

rr_AverageAnnualReturnYear01

6.44%

Past 5 Years

rr_AverageAnnualReturnYear05

15.06%

Past 10 Years

rr_AverageAnnualReturnYear10

8.65%

(Natixis U.S. Equity Opportunities Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

(1.29%)

Past 5 Years

rr_AverageAnnualReturnYear05

12.63%

Past 10 Years

rr_AverageAnnualReturnYear10

7.45%

(Natixis U.S. Equity Opportunities Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

8.39%

Past 5 Years

rr_AverageAnnualReturnYear05

11.92%

Past 10 Years

rr_AverageAnnualReturnYear10

6.98%

(Natixis U.S. Equity Opportunities Fund) | Class B

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

5.00%

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.80%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.26%

^[4],[6]

Fee/expense recovery

rr_Component1OtherExpensesOverAssets

0.02%

Remainder of other expenses

rr_Component2OtherExpensesOverAssets

0.24%

Total annual fund operating expenses

rr_ExpensesOverAssets

2.06%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

2.06%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

709

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

946

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,308

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,197

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

209

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

646

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,108

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,197

Past 1 Year

rr_AverageAnnualReturnYear01

8.38%

Past 5 Years

rr_AverageAnnualReturnYear05

15.35%

Past 10 Years

rr_AverageAnnualReturnYear10

8.49%

(Natixis U.S. Equity Opportunities 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.80%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.26%

^[4],[6]

Fee/expense recovery

rr_Component1OtherExpensesOverAssets

0.01%

Remainder of other expenses

rr_Component2OtherExpensesOverAssets

0.25%

Total annual fund operating expenses

rr_ExpensesOverAssets

2.06%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

2.06%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

309

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

646

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,108

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,390

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

209

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

646

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,108

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,390

Past 1 Year

rr_AverageAnnualReturnYear01

11.37%

Past 5 Years

rr_AverageAnnualReturnYear05

15.57%

Past 10 Years

rr_AverageAnnualReturnYear10

8.48%

(Natixis U.S. Equity Opportunities 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.80%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.26%

^[4],[6]

Fee/expense recovery

rr_Component1OtherExpensesOverAssets

none

Remainder of other expenses

rr_Component2OtherExpensesOverAssets

0.26%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.06%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.06%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

108

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

337

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

585

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,294

Past 1 Year

rr_AverageAnnualReturnYear01

13.25%

Past 5 Years

rr_AverageAnnualReturnYear05

16.74%

Past 10 Years

rr_AverageAnnualReturnYear10

9.62%

(Vaughan Nelson Small Cap Value Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks capital appreciation.

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 $50,000 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 65 of the Prospectus and on page 118 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

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 $50,000 in the Natixis Fund Complex.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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, 2016

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

The expense information shown in the table differs from the expense information disclosed in the Fund's financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.

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 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:

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 58% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

58.00%

Strategy [Heading]

rr_StrategyHeading

Investments, Risks and Performance

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund normally will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in the equity securities, including common stocks and preferred stocks, of "small-cap companies." Equity securities may take the form of stock in corporations, limited partnership interests, interests in limited liability companies, REITs or other trusts and other similar securities. Currently, the Fund defines a small-cap company to be one whose market capitalization, at the time of purchase, either falls within the capitalization range of the Russell 2000® Value Index, an unmanaged index that measures the performance of those Russell 2000® companies with lower price-to-book ratios and lower forecasted growth values, or is $3.5 billion or less. While the market capitalization range for the Russell 2000® Value Index fluctuates, at December 31, 2014, it was $19 million to $4.9 billion. The Fund may, however, invest in companies with large capitalizations.

Vaughan Nelson Investment Management, L.P. ("Vaughan Nelson") invests in small-capitalization companies with a focus on those companies meeting Vaughan Nelson's return expectations. Vaughan Nelson uses a bottom-up value oriented investment process in constructing the Fund's portfolio. Vaughan Nelson seeks companies with the following characteristics, although not all of the companies selected will have these attributes:

• Companies earning a positive return on capital with stable-to-improving returns.

• Companies valued at a discount to their asset value.

• Companies with an attractive and sustainable dividend level.

In selecting investments for the Fund, Vaughan Nelson generally employs the following strategies:

• Value-driven investment philosophy that selects stocks selling at a relatively low value based on discounted cash flow models. Vaughan Nelson selects companies that it believes are out of favor or misunderstood.

• Vaughan Nelson starts with an investment universe of 5,000 securities. Vaughan Nelson then uses value-driven screens to create a research universe of companies with market capitalizations of at least $100 million.

• Vaughan Nelson uses fundamental analysis to construct a portfolio of 60 to 80 securities that, in the opinion of Vaughan Nelson, is made up of quality companies with the potential to provide significant increases in share price over a three year period.

• Vaughan Nelson will generally sell a security when it reaches Vaughan Nelson's price target or when the issuer shows a change in financial condition, competitive pressures, poor management decisions or internal or external forces reducing future expected returns from the investment thesis.

The Fund may also:

• Invest in convertible preferred stock and convertible debt securities.

• Invest in foreign securities, including emerging market securities.

• Invest in real estate investment trusts ("REITs").

• Invest in securities offered in initial public offerings ("IPOs").

Risk [Heading]

rr_RiskHeading

Principal Investment 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.

Emerging Markets Risk: In addition to the risks of investing in foreign investments generally, emerging markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, currency exchange restrictions, sanctions by the U.S. government and an issuer's unwillingness or inability to make principal or interest payments on its obligations. Emerging markets companies may be smaller and have shorter operating histories than companies in developed markets.

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. Securities issued in IPOs tend to involve greater market risk than other equity securities due, in part, to public perception and the lack of publicly available information and trading history. Value stocks can perform differently from the market as a whole and from other types of stocks. Value stocks also present the risk that their lower valuations fairly reflect their business prospects and that investors will not agree that the stocks represent favorable investment opportunities, and they may fall out of favor with investors and underperform growth stocks during any given period. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock.

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 also are subject to foreign currency fluctuations and other foreign currency-related risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Liquidity issues may also make it difficult to value the Fund's investments.

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 or portfolio 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.

REITs Risk: Investments in the real estate industry, including REITs, are particularly sensitive to economic downturns and are sensitive to factors such as changes in real estate values, property taxes and tax laws, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents and the management skill and creditworthiness of the issuer. Companies in the real estate industry also may be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or mortgage loans held by the REIT. REITs are also subject to default and prepayment risk. Many REITs are highly leveraged, increasing their risk. The Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund.

Small-Cap Companies Risk: Small-cap companies are more likely than larger companies to have limited product lines, markets or financial resources, or to depend on a small, inexperienced management group. Stocks of these companies often trade less frequently and in limited volume and their prices may fluctuate more than stocks of larger companies. Stocks of small-cap companies may therefore be more vulnerable to adverse developments than those of larger companies.

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

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 comparing the Fund's one-year, five-year and ten-year performance with 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.

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class A Shares

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

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.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return:
Third Quarter 2009, 18.56%

Lowest Quarterly Return:
Third Quarter 2011, -19.60%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns (for the periods ended December 31, 2014)

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

Class B total returns in the table below do not reflect the automatic conversion of Class B shares to Class A shares after eight years.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

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-advantaged 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. The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from losses on a sale of Fund shares at the end of the measurement period. Index performance reflects no deduction for fees, expenses or taxes.

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-advantaged arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

The Return After Taxes on Distributions and Sale of Fund Shares for the 1-year period exceeds the Return Before Taxes due to an assumed tax benefit from losses on a sale of Fund shares at the end of the measurement period.

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.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown for only one class of the Fund.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

ngam.natixis.com

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-225-5478

(Vaughan Nelson Small Cap Value Fund) | Russell 2000® Value Index

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

4.22%

Past 5 Years

rr_AverageAnnualReturnYear05

14.26%

Past 10 Years

rr_AverageAnnualReturnYear10

6.89%

(Vaughan Nelson Small Cap Value Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.90%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.22%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.14%

^[8]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.51%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[9]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.51%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

720

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

1,025

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,351

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,273

Annual Return 2005

rr_AnnualReturn2005

10.08%

Annual Return 2006

rr_AnnualReturn2006

18.09%

Annual Return 2007

rr_AnnualReturn2007

5.84%

Annual Return 2008

rr_AnnualReturn2008

(21.11%)

Annual Return 2009

rr_AnnualReturn2009

28.30%

Annual Return 2010

rr_AnnualReturn2010

23.67%

Annual Return 2011

rr_AnnualReturn2011

(3.77%)

Annual Return 2012

rr_AnnualReturn2012

14.93%

Annual Return 2013

rr_AnnualReturn2013

39.01%

Annual Return 2014

rr_AnnualReturn2014

8.79%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarterly Return:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.56%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return:

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(19.60%)

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Past 1 Year

rr_AverageAnnualReturnYear01

2.54%

Past 5 Years

rr_AverageAnnualReturnYear05

14.29%

Past 10 Years

rr_AverageAnnualReturnYear10

10.50%

(Vaughan Nelson Small Cap Value Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

(1.25%)

Past 5 Years

rr_AverageAnnualReturnYear05

10.56%

Past 10 Years

rr_AverageAnnualReturnYear10

8.68%

(Vaughan Nelson Small Cap Value Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

Past 1 Year

rr_AverageAnnualReturnYear01

4.36%

Past 5 Years

rr_AverageAnnualReturnYear05

10.97%

Past 10 Years

rr_AverageAnnualReturnYear10

8.44%

(Vaughan Nelson Small Cap Value Fund) | Class B

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

5.00%

Redemption fees

rr_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.90%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.22%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.14%

^[8]

Total annual fund operating expenses

rr_ExpensesOverAssets

2.26%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[9]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

2.26%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

729

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

1,006

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,410

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,407

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

229

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

706

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,210

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,407

Past 1 Year

rr_AverageAnnualReturnYear01

3.51%

Past 5 Years

rr_AverageAnnualReturnYear05

14.60%

Past 10 Years

rr_AverageAnnualReturnYear10

10.33%

(Vaughan Nelson Small Cap Value 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.90%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.22%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.14%

^[8]

Total annual fund operating expenses

rr_ExpensesOverAssets

2.26%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[9]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

2.26%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

329

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

706

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,210

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,595

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

229

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

706

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,210

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,595

Past 1 Year

rr_AverageAnnualReturnYear01

7.07%

Past 5 Years

rr_AverageAnnualReturnYear05

14.78%

Past 10 Years

rr_AverageAnnualReturnYear10

10.33%

(Vaughan Nelson Small Cap Value 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_RedemptionFee

none

Management fees

rr_ManagementFeesOverAssets

0.90%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses Over Assets

rr_OtherExpensesOverAssets

0.22%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.14%

^[8]

Total annual fund operating expenses

rr_ExpensesOverAssets

1.26%

Fee waiver and/or expense reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[9]

Total annual fund operating expenses after fee waiver and/or expense reimbursement

rr_NetExpensesOverAssets

1.26%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

128

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

400

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

692

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,523

Past 1 Year

rr_AverageAnnualReturnYear01

9.04%

Past 5 Years

rr_AverageAnnualReturnYear05

15.94%

Past 10 Years

rr_AverageAnnualReturnYear10

11.41%

^[3]

[1] A 1.00% contingent deferred sales charge ("CDSC") may apply to certain purchases of Class A shares of $1,000,000 or more that are redeemed within eighteen months of the date of purchase.

[2] The Fund's investment adviser has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 1.25%, 2.00% and 1.00% 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, 2016 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Fund's investment 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 1.25%, 2.00% and 1.00% 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.

[3] Prior to the inception of Class Y shares (12/3/12), performance is that of Class A shares and reflects the higher net expenses of that share class.

[4] Other expenses have been restated to reflect current custodian and transfer agency fees for the Fund effective October 1, 2014.

[5] The Fund's investment adviser has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 1.45% and 2.20% of the Fund's average daily net assets for Class A and C 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, 2016 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Fund's investment 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 1.45% and 2.20% of the Fund's average daily net assets for Class A and C 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.

[6] The expense information shown in the table above includes acquired fund fees and expenses of less than 0.01%; the ratios may differ from the expense information disclosed in the Fund's financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.

[7] The Fund's investment 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%, 2.05% and 1.05% of the Fund's average daily net assets for Class A, B, 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, 2016 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Fund's investment 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%, 2.05% and 1.05% of the Fund's average daily net assets for Class A, B, 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.

[8] The expense information shown in the table differs from the expense information disclosed in the Fund's financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.

[9] The Fund's investment adviser has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 1.45%, 2.20%, 2.20% and 1.20% of the Fund's average daily net assets for Class A, B, 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, 2016 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Fund's investment 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 1.45%, 2.20%, 2.20% and 1.20% of the Fund's average daily net assets for Class A, B, 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.