rr_ExpenseExampleHeading

Example

rr_ExpenseExampleByYearCaption

If shares are redeemed:

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverRate

49.00%

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 and fixed-income securities of U.S. and foreign issuers. Equity securities purchased by the Fund may include common stocks, preferred stocks, depositary receipts, warrants, securities convertible into common or preferred stocks, interests in real estate investment trusts ("REITs") and/or real estate-related securities and other equity-like interests in an issuer. The Fund will invest a significant portion of its assets outside the U.S., including securities of issuers located in emerging market countries.

In deciding which equity securities to buy and sell, the Adviser generally looks to purchase quality companies at attractive valuations with the potential to grow intrinsic value over time. The Adviser uses discounted cash flow analysis, among other methods of analysis, to determine a company's intrinsic value.

In deciding which fixed-income securities to buy and sell, the Adviser generally looks for securities that it believes are undervalued and have the potential for credit upgrades, which may include securities that are below investment grade (also known as "junk bonds"). The Fund may also invest in foreign currencies, collateralized mortgage obligations, zero-coupon securities, when-issued securities, REITs, securities issued pursuant to Rule 144 under the Securities Act of 1933 ("Rule 144A securities") and mortgage-related securities. The Fund may also engage in active and frequent trading of securities and engage in options or foreign currency transactions for hedging and investment purposes and futures transactions, foreign currency transactions and swap transactions (including credit default swaps). Frequent trading may produce high transaction costs and a high level of taxable capital gains, which may lower the Fund's return. The Adviser may hedge currency risk for the Fund (including "cross hedging" between two or more foreign currencies) if it believes the outlook for a particular foreign currency is unfavorable. The Adviser may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged. Except as provided above, the Fund is not limited in the percentage of its assets that it may invest in these instruments.

Bar Chart and Performance Table [Heading]

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.

Below Investment Grade Fixed-Income Securities Risk: The Fund's investments in below investment grade fixed-income securities, also known as "junk bonds," may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, credit risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is predominantly speculative for below investment grade fixed-income securities.

Credit/Counterparty Risk: Credit risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivatives or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risks with respect to the counterparties of its derivative transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee of an exchange clearing house, are not available in connection with over-the-counter ("OTC") derivative transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its direct counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Currency Risk: Fluctuations in the exchange rates between different currencies may negatively affect an investment. The Fund may be subject to currency risk because it may invest in currency-related instruments and may invest in securities or other instruments denominated in, or receive 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.

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, such as forward currency contracts, options and futures transactions and swap transactions 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 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.

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. 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. Rule 144A securities may be less liquid than other equity securities.

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.

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. The value of zero-coupon securities and securities with longer maturities are generally more sensitive to fluctuations in interest rates 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, negatively impacting the performance of the Fund.

Issuer Risk: The value of the Fund's investments may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods and services.

Leverage Risk: Use of derivative instruments may involve leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset-price movements into larger changes in value. 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. Events that may lead to increased redemptions, such as market disruptions, 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. 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 Securities Risk: In addition to the risks associated with investments in fixed-income securities generally (for example, credit, liquidity and valuation risk), mortgage-related securities are subject to the risks of the mortgages 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 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.

rr_BarChartAndPerformanceTableHeading

Risk/Return Bar Chart and Table

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class Y Shares

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return: Second Quarter 2009, 19.91%

Lowest Quarterly Return: Third Quarter 2008, -19.64%

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Prior to the inception of Class A and Class C shares (February 1, 2006), performance is that of Class Y shares, restated to reflect the higher net expenses and sales loads of Class A and Class C shares, respectively.

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 shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. The after-tax returns are shown for only one class of the Fund. After-tax returns for the other classes of the Fund will vary. Index performance reflects no deduction for fees, expenses or taxes.

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 One Class of after Tax Shown [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

rr_PerformanceTableOneClassOfAfterTaxShown

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.

rr_PerformanceAvailabilityPhone

800-225-5478

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear05

10.81%

rr_AverageAnnualReturnYear01

(0.48%)

rr_AverageAnnualReturnYear10

3.08%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

rr_ManagementFeesOverAssets

0.75%

rr_FeeWaiverOrReimbursementOverAssets

none

^[3]

rr_ExpenseExampleYear01

686

rr_ExpenseExampleYear05

1,177

rr_AverageAnnualReturnYear01

(2.71%)

rr_AverageAnnualReturnYear10

7.76%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

rr_ManagementFeesOverAssets

0.75%

rr_FeeWaiverOrReimbursementOverAssets

none

^[3]

rr_ExpenseExampleYear01

294

rr_ExpenseExampleYear05

1,032

rr_ExpenseExampleNoRedemptionYear01

194

rr_ExpenseExampleNoRedemptionYear05

1,032

rr_AverageAnnualReturnYear01

1.52%

rr_AverageAnnualReturnYear10

7.60%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

none

rr_ManagementFeesOverAssets

0.75%

rr_FeeWaiverOrReimbursementOverAssets

none

^[3]

rr_ExpenseExampleYear01

93

Highest Quarterly Return, Label

rr_ExpenseExampleYear05

rr_AnnualReturn2005

rr_AnnualReturn2007

rr_AnnualReturn2009

rr_AnnualReturn2011

rr_AnnualReturn2013

rr_HighestQuarterlyReturnLabel

Highest Quarterly Return: Second Quarter 2009, 19.91%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(19.64%)

rr_AverageAnnualReturnYear01

3.53%

rr_AverageAnnualReturnYear10

8.67%

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear05

10.06%

rr_AverageAnnualReturnYear01

2.97%

rr_AverageAnnualReturnYear10

6.81%

Objective, Primary [Text Block]

rr_RiskReturnAbstract

rr_ObjectivePrimaryTextBlock

The Fund's investment goal is long-term growth of capital.

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 28 of the Prospectus and on page 113 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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)

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 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, except that the example for Class N shares is based on Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement for the first year and on the Total Annual Fund Operating Expenses for the remaining periods. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example, No Redemption, By Year, Caption [Text]

rr_ExpenseExampleNoRedemptionByYearCaption

If shares are not redeemed:

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 14% of the average value of its portfolio.

Strategy [Heading]

rr_StrategyHeading

Investments, Risks and Performance

Principal Investment Strategies

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

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, ten-year and life-of-class periods (as applicable) 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 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.

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 shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. The after-tax returns are shown for only one class of the Fund. After-tax returns for the other classes of the Fund will vary. Index performance reflects no deduction for fees, expenses or taxes.

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 One Class of after Tax Shown [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

rr_PerformanceTableOneClassOfAfterTaxShown

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.

rr_PerformanceAvailabilityPhone

800-225-5478

rr_RiskReturnAbstract

Life of Fund / Life of Class N

rr_AverageAnnualReturnYear05

15.81%

rr_AverageAnnualReturnSinceInception

20.74%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

rr_ManagementFeesOverAssets

rr_FeeWaiverOrReimbursementOverAssets

none

^[4],[5]

rr_ExpenseExampleYear01

665

Highest Quarterly Return, Label

rr_ExpenseExampleYear05

rr_AnnualReturn2005

rr_AnnualReturn2007

rr_AnnualReturn2009

rr_AnnualReturn2011

rr_AnnualReturn2013

rr_HighestQuarterlyReturnLabel

Highest Quarterly Returns: Third Quarter 2010, 14.73%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(26.00%)

rr_AverageAnnualReturnYear01

4.64%

rr_AverageAnnualReturnYear10

5.22%

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear05

14.09%

rr_AverageAnnualReturnYear01

2.73%

rr_AverageAnnualReturnYear10

4.18%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

5.00%

rr_ManagementFeesOverAssets

rr_FeeWaiverOrReimbursementOverAssets

none

^[4],[5]

rr_ExpenseExampleYear01

672

rr_ExpenseExampleYear05

1,118

rr_ExpenseExampleNoRedemptionYear01

172

rr_ExpenseExampleNoRedemptionYear05

918

rr_AverageAnnualReturnYear01

5.13%

rr_AverageAnnualReturnYear10

5.06%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

rr_ManagementFeesOverAssets

rr_FeeWaiverOrReimbursementOverAssets

none

^[4],[5]

rr_ExpenseExampleYear01

272

rr_ExpenseExampleYear05

918

rr_ExpenseExampleNoRedemptionYear01

172

rr_ExpenseExampleNoRedemptionYear05

918

rr_AverageAnnualReturnYear01

9.14%

rr_AverageAnnualReturnYear10

5.07%

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

none

rr_ManagementFeesOverAssets

rr_FeeWaiverOrReimbursementOverAssets

3.11%

^[4],[5]

rr_ExpenseExampleYear01

63

rr_ExpenseExampleYear05

1,661

rr_AverageAnnualReturnYear01

11.12%

rr_AverageAnnualReturnYear10

rr_AverageAnnualReturnInceptionDate

Feb. 01, 2013

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

none

rr_ManagementFeesOverAssets

rr_FeeWaiverOrReimbursementOverAssets

none

^[4],[5]

rr_ExpenseExampleYear01

70

rr_ExpenseExampleYear05

384

rr_AverageAnnualReturnYear01

11.27%

rr_AverageAnnualReturnYear10

6.19%

Objective, Primary [Text Block]

rr_RiskReturnAbstract

rr_ObjectivePrimaryTextBlock

The Fund's investment objective is long-term growth of capital and income.

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 28 of the Prospectus and on page 113 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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)

rr_ExpenseExampleHeading

Example

rr_ExpenseExampleByYearCaption

If shares are redeemed:

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverRate

28.00%

rr_StrategyNarrativeTextBlock

Under normal market conditions, the Fund will invest primarily in equity securities, including common stocks, convertible securities and warrants.

In deciding which securities to buy and sell, the Adviser generally looks for companies that it believes are undervalued by the market in relation to earnings, dividends, assets and/or growth prospects. The Fund's investments may include companies that have suffered significant business problems but that the Adviser believes have favorable prospects for recovery. The Adviser seeks to identify companies that it believes are, among other things, attractively valued based on the Adviser's estimate of intrinsic value. The Adviser generally seeks to find value by selecting individual stocks that it believes are attractive, rather than by attempting to achieve investment growth by rotating the Fund's holdings among various sectors of the economy.

The Fund may also invest up to 20% of its assets in securities of foreign issuers including emerging market securities, invest in options for hedging and investment purposes, real estate investment trusts ("REITs") and securities issued pursuant to Rule 144 under the Securities Act of 1933 ("Rule 144A securities"). Except as provided above, the Fund is not limited in the percentage of its assets that it may invest in these instruments.

Bar Chart and Performance Table [Heading]

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.

Credit/Counterparty Risk: Credit risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivatives or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risks with respect to the counterparties of its derivative transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee of an exchange clearing house, are not available in connection with over-the-counter ("OTC") derivative transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its direct counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Currency Risk: Fluctuations in the exchange rates between different currencies may negatively affect an investment. The Fund may be subject to currency risk because it may invest in currency-related instruments and may invest in securities or other instruments denominated in, or receive 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.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including options) 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, such as options transactions involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for over-the-counter 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.

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.

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.

Issuer Risk: The value of the Fund's investments may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods and services.

Leverage Risk: Use of derivative instruments may involve leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset-price movements into larger changes in value. 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. Events that may lead to increased redemptions, such as market disruptions, 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. 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 Capitalization Risk: The general risks associated with corporate income-producing securities are particularly pronounced for securities issued by companies with smaller market capitalizations. These companies may have limited product lines, markets or financial resources or they may depend on a few key employees. As a result, they may be subject to greater levels of credit, market and issuer risk. Securities of smaller companies may trade less frequently and in lesser volume than more widely-held securities and their values may fluctuate more sharply than other securities. Further, securities of smaller companies may perform differently in different cycles than securities of larger companies. Companies with medium-sized market capitalizations may have risks similar to those of smaller companies.

rr_BarChartAndPerformanceTableHeading

Risk/Return Bar Chart and Table

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class Y Shares

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return: Third Quarter 2009, 16.56%

Lowest Quarterly Return: Fourth Quarter 2008, -19.58%

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.

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

Index performance reflects no deduction for fees, expenses or taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

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, ten-year and life-of-class periods (as applicable) compare to those of a broad measure of market performance.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

ngam.natixis.com

rr_AverageAnnualReturnYear01

13.45%

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

rr_AverageAnnualReturnYear10

7.30%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

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

rr_ExpensesOverAssets

0.96%

rr_NetExpensesOverAssets

0.96%

rr_ExpenseExampleYear03

863

rr_ExpenseExampleYear10

1,685

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

rr_AverageAnnualReturnYear05

12.72%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

rr_ExpensesOverAssets

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

rr_NetExpensesOverAssets

rr_ExpenseExampleYear03

839

rr_ExpenseExampleYear10

1,821

rr_ExpenseExampleNoRedemptionYear03

539

rr_ExpenseExampleNoRedemptionYear10

1,821

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

rr_AverageAnnualReturnYear05

12.96%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

rr_ExpensesOverAssets

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

rr_NetExpensesOverAssets

rr_ExpenseExampleYear03

539

rr_ExpenseExampleYear10

2,019

rr_ExpenseExampleNoRedemptionYear03

539

rr_ExpenseExampleNoRedemptionYear10

2,019

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

rr_AverageAnnualReturnYear05

13.21%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

none

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

rr_ExpensesOverAssets

0.57%

rr_NetExpensesOverAssets

0.57%

rr_ExpenseExampleYear03

183

rr_ExpenseExampleYear10

714

Life of Fund / Life of Class N

rr_AverageAnnualReturnYear05

rr_AverageAnnualReturnSinceInception

19.08%

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

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

none

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

rr_ExpensesOverAssets

0.71%

rr_NetExpensesOverAssets

0.71%

rr_ExpenseExampleYear03

227

Lowest Quarterly Return, Label

rr_ExpenseExampleYear10

rr_AnnualReturn2006

rr_AnnualReturn2008

rr_AnnualReturn2010

rr_AnnualReturn2012

rr_AnnualReturn2014

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.56%

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return: Fourth Quarter 2008, -19.58%

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

rr_AverageAnnualReturnYear05

14.35%

rr_AverageAnnualReturnYear01

7.88%

rr_AverageAnnualReturnYear10

7.98%

rr_RiskReturnAbstract

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

rr_AverageAnnualReturnYear05

11.53%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

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

rr_ExpensesOverAssets

1.21%

rr_NetExpensesOverAssets

1.21%

rr_ExpenseExampleYear03

384

rr_ExpenseExampleYear10

1,466

Expense Breakpoint Discounts [Text]

rr_AverageAnnualReturnYear05

13.80%

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Expense [Heading]

rr_ExpenseHeading

Fund Fees & Expenses

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.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees

(fees paid directly from your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2016

rr_ExpenseExampleHeading

Example

rr_ExpenseExampleByYearCaption

If shares are redeemed:

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverRate

59.00%

rr_StrategyNarrativeTextBlock

Under normal market conditions, the Fund will invest at least 65% of its assets in below investment grade fixed-income securities (commonly known as "junk bonds"). Below investment grade fixed-income securities are rated below investment grade quality (i.e., none of the three major ratings agencies (Moody's Investors Service, Inc. ("Moody's"), Fitch Investors Services, Inc. ("Fitch") or Standard and Poor's Ratings Group ("S&P")), have rated the securities in one of its top four rating categories) or, if the security is unrated, are determined by the Adviser to be of comparable quality. There is no minimum rating for the securities in which the Fund may invest. The Fund will normally invest at least 65% of its assets in U.S. corporate or U.S. dollar-denominated foreign fixed-income securities. The Fund may also invest up to 20% of its assets in foreign currency-denominated fixed-income securities, including those in emerging markets and related currency hedging transactions. The Adviser may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

The Adviser performs its own extensive credit analysis to determine the creditworthiness and potential for capital appreciation of a security. The Fund's management minimizes both market timing and interest rate forecasting. Instead, it uses a strategy based on gaining a thorough understanding of industry and company dynamics as well as individual security characteristics such as issuer debt and debt maturity schedules, earnings prospects, responsiveness to changes in interest rates, experience and perceived strength of management, borrowing requirements and liquidation value, market price in relation to cash flow, interest and dividends.

In deciding which securities to buy and sell, the Adviser will consider, among other things, the financial strength of the issuer, current interest rates, current valuations, the Adviser's expectations regarding future changes in interest rates and comparisons of the level of risk associated with particular investments with the Adviser's expectations concerning the potential return of those investments.

In selecting investments for the Fund, the Adviser utilizes the skills of its in-house team of more than 30 research analysts to cover a broad universe of industries, companies and markets. The Fund's portfolio managers take advantage of these extensive resources to identify securities that meet the Fund's investment criteria. The Adviser employs a selection strategy that focuses on a value-driven, bottom-up approach to identify securities that provide an opportunity for both generous yields and capital appreciation. The Adviser analyzes an individual company's potential for positive financial news to determine if it has growth potential. Examples of positive financial news include an upward turn in the business cycle, improvement in cash flows, rising profits or the awarding of new contracts. The Adviser emphasizes in-depth credit analysis, appreciation potential and diversification in its bond selection. Each bond is evaluated to assess the ability of its issuer to pay interest and, ultimately, principal (which helps the Fund generate an ongoing flow of income). The Adviser also assesses a bond's relation to market conditions within its industry and favors bonds whose prices may benefit from positive business developments. The Adviser seeks to diversify the Fund's holdings to reduce the inherent risk in below investment grade fixed-income securities.

In connection with its principal investment strategies, the Fund may also invest in structured notes, zero-coupon securities, pay-in-kind securities, securities issued pursuant to Rule 144 under the Securities Act of 1933 ("Rule 144A securities"), futures, forward contracts and swaps (including credit default swaps). Except as provided above, the Fund is not limited in the percentage of its assets that it may invest in these instruments.

Bar Chart and Performance Table [Heading]

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.

Below Investment Grade Fixed-Income Securities Risk: The Fund's investments in below investment grade fixed-income securities, also known as "junk bonds," may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, credit risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is predominantly speculative for below investment grade fixed-income securities.

Credit/Counterparty Risk: Credit risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivatives or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risks with respect to the counterparties of its derivative transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee of an exchange clearing house, are not available in connection with over-the-counter ("OTC") derivative transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its direct counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Currency Risk: Fluctuations in the exchange rates between different currencies may negatively affect an investment. The Fund may be subject to currency risk because it may invest in currency-related instruments and may invest in securities or other instruments denominated in, or receive 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.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including futures, forwards and swaps (including credit default swaps)) 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, such as forward currency contracts, structured notes, futures transactions and swap transactions 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 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.

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.

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. Rule 144A securities and structured notes may be more illiquid than other fixed-income securities. Zero-coupon bonds may be subject to these risks 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.

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. The value of zero-coupon bonds may be more sensitive to fluctuations in interest rates 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, negatively impacting the performance of the Fund.

Issuer Risk: The value of the Fund's investments may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods and services.

Leverage Risk: Use of derivative instruments may involve leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset-price movements into larger changes in value. 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. Events that may lead to increased redemptions, such as market disruptions, 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. 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.

rr_BarChartAndPerformanceTableHeading

Risk/Return Bar Chart and Table

Bar Chart [Heading]

rr_BarChartHeading

Total Returns for Class A Shares

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Highest Quarterly Return: Second Quarter 2009, 16.38%

Lowest Quarterly Return: Fourth Quarter 2008, -18.10%

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.

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

Index performance reflects no deduction for fees, expenses or taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

Performance Table One Class of after Tax Shown [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

rr_PerformanceTableOneClassOfAfterTaxShown

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

rr_PerformanceAvailabilityPhone

800-225-5478

rr_RiskReturnAbstract

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

rr_AverageAnnualReturnYear05

9.03%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

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

rr_ExpensesOverAssets

1.12%

rr_NetExpensesOverAssets

1.12%

rr_ExpenseExampleYear03

790

Lowest Quarterly Return, Label

rr_ExpenseExampleYear10

rr_AnnualReturn2006

rr_AnnualReturn2008

rr_AnnualReturn2010

rr_AnnualReturn2012

rr_AnnualReturn2014

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.38%

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return: Fourth Quarter 2008, -18.10%

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

rr_AverageAnnualReturnYear05

7.04%

rr_AverageAnnualReturnYear01

(2.92%)

rr_AverageAnnualReturnYear10

3.66%

rr_RiskReturnAbstract

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

rr_AverageAnnualReturnYear05

4.46%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

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

rr_ExpensesOverAssets

1.88%

rr_NetExpensesOverAssets

1.88%

rr_ExpenseExampleYear03

891

rr_ExpenseExampleYear10

2,003

rr_ExpenseExampleNoRedemptionYear03

591

rr_ExpenseExampleNoRedemptionYear10

2,003

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

rr_AverageAnnualReturnYear05

6.93%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

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

rr_ExpensesOverAssets

1.87%

rr_NetExpensesOverAssets

1.87%

rr_ExpenseExampleYear03

588

rr_ExpenseExampleYear10

2,190

rr_ExpenseExampleNoRedemptionYear03

588

rr_ExpenseExampleNoRedemptionYear10

2,190

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

rr_AverageAnnualReturnYear05

7.20%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

none

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

rr_ExpensesOverAssets

0.87%

rr_NetExpensesOverAssets

0.87%

rr_ExpenseExampleYear03

278

rr_ExpenseExampleYear10

1,073

Expense Breakpoint Discounts [Text]

rr_AverageAnnualReturnYear05

8.31%

Objective [Heading]

rr_ObjectiveHeading

Investment Goal

Expense [Heading]

rr_ExpenseHeading

Fund Fees & Expenses

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.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees

(fees paid directly from your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

January 31, 2016

rr_ExpenseExampleHeading

Example

rr_ExpenseExampleByYearCaption

If shares are redeemed:

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverRate

51.00%

rr_StrategyNarrativeTextBlock

Under normal market conditions, the Fund expects to invest at least 80% of its net assets (plus any borrowings made for investment purposes) in fixed-income securities. The Fund is non-diversified, which means that it may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers than a diversified fund. The Fund invests primarily (at least 65% of its net assets) in fixed-income securities of issuers located outside the United States. Securities held by the Fund may be denominated in any currency and may be of issuers located in emerging market countries. The Fund invests primarily in investment grade fixed-income securities. "Investment grade" securities are those securities that are rated as such at the time of purchase by at least one of the three major rating agencies (Moody's Investors Service, Inc. ("Moody's"), Fitch Investors Services, Inc. ("Fitch") or Standard and Poor's Ratings Group ("S&P")) or, if unrated, are determined by the Adviser to be of comparable quality, although the Fund may invest up to 35% of its assets in below investment grade fixed-income securities (commonly known as "junk bonds"). Below investment grade fixed-income securities are rated below investment grade quality (i.e., none of the three major ratings agencies (Moody's, Fitch or S&P) have rated the securities in one of its top four ratings categories) or, if unrated, are determined by the Adviser to be of comparable quality. There is no minimum rating for securities in which the Fund will invest. The Fund may invest in fixed-income securities of any maturity. The Fund may also invest in foreign currencies and may engage in other foreign currency transactions for investment or for hedging purposes.

In deciding which securities to buy and sell, the Adviser may consider, among other things, the stability and volatility of a country's bond markets, the financial strength of the issuer, current interest rates, current valuations, currency considerations, the Adviser's expectations regarding general trends in interest rates and comparisons of the level of risk associated with particular investments with the Adviser's expectations concerning the potential return of those investments.

Three themes typically drive the Fund's investment approach. First, the Adviser generally seeks fixed-income securities of issuers whose credit profiles it believes are improving. The Adviser's credit research team provides deep fundamental and quantitative analysis as well as ratings on over 1,000 credits worldwide. The broad coverage combined with the objective to identify attractive investment opportunities makes this an important component of the investment approach. Second, the Adviser analyzes political, economic, and other fundamental factors and combines this analysis with a comparison of the yield spreads of various fixed-income securities in an effort to find securities that it believes may produce attractive returns for the Fund in comparison to their risk. Third, if a security that is believed to be attractive is denominated in a foreign currency, the Adviser analyzes whether to accept or to hedge the currency risk. In certain instances, the Adviser may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged.

The fixed-income securities in which the Fund may invest include public or private debt obligations issued or guaranteed by U.S. or non-U.S. issuers, including, but not limited to, corporations, governments (including their agencies, instrumentalities and sponsored entities), supranational entities, partnerships and trusts. The Fund may also invest in preferred stocks, convertible securities, when-issued securities, securities issued pursuant to Rule 144 under the Securities Act of 1933 ("Rule 144A securities"), mortgage- or asset-backed securities and zero-coupon securities issued by any of the above-named entities.

In connection with its principal investment strategies, the Fund may also invest in inflation- and index-linked securities, senior loans, structured notes, common stocks (limited to shares acquired as a result of a financial restructuring, bankruptcy or similar transaction or from an exchange or conversion of a permissible security held in the portfolio), and derivatives, including options, futures, options on futures, forward contracts and swap contracts (including credit default swaps). The Fund may also engage in active and frequent trading of securities. Frequent trading may produce high transaction costs and a high level of taxable capital gains, which may lower the Fund's return. Except as provided above, the Fund is not limited in the percentage of its assets that it may invest in these instruments.

Performance 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.

Below Investment Grade Fixed-Income Securities Risk: The Fund's investments in below investment grade fixed-income securities, also known as "junk bonds," may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, credit risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is predominantly speculative for below investment grade fixed-income securities.

Credit/Counterparty Risk: Credit risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivatives or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risks with respect to the counterparties of its derivative transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee of an exchange clearing house, are not available in connection with over-the-counter ("OTC") derivative transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its direct counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Currency Risk: Fluctuations in the exchange rates between different currencies may negatively affect an investment. The Fund may be subject to currency risk because it may invest in currency-related instruments and may invest in securities or other instruments denominated in, or receive 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.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including options, futures, options on futures, forward contracts and swap contracts (including credit default swaps)) 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, such as forward currency contracts, structured notes, options and futures transactions and swap transactions 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 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.

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. 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. Rule 144A securities and structured notes may be more illiquid than other fixed-income securities. Zero-coupon bonds may be subject to these risks 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.

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. Senior loans typically have adjustable interest rates. As a result, it is expected that the values of senior loans held by the Fund will fluctuate less in response to interest rate changes than will fixed-rate debt securities; however, the interest rates paid by these loans will generally decrease if interest rates fall. Senior loans and other fixed-income securities are subject to the risk that borrowers pay off the debts sooner than expected. The value of zero-coupon bonds may be more sensitive to fluctuations in interest rates 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, negatively impacting the performance of the Fund.

Issuer Risk: The value of the Fund's investments may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods and services.

Leverage Risk: Use of derivative instruments may involve leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset-price movements into larger changes in value. 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. Events that may lead to increased redemptions, such as market disruptions, 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. 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.

Non-Diversification Risk: Compared with other mutual funds, the Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, the Fund may have more risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's NAV.

Risk Lose Money [Text]

rr_RiskLoseMoney

You may lose money by investing in the Fund.

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-fund periods compare to those of a broad measure of market performance. The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated performance information is available online at ngam.natixis.com and/or by calling the Fund toll-free at 800-225-5478.

The chart does not reflect any sales charge that you may be required to pay when you buy or redeem the Fund's shares. A sales charge will reduce your return.

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.

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns

(for the periods ended December 31, 2014)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

Index performance reflects no deduction for fees, expenses or taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts.

Performance Table One Class of after Tax Shown [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

rr_PerformanceTableOneClassOfAfterTaxShown

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

rr_PerformanceAvailabilityPhone

800-225-5478

rr_RiskReturnAbstract

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

rr_AverageAnnualReturnYear05

1.38%

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

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

rr_ExpensesOverAssets

2.37%

rr_NetExpensesOverAssets

1.06%

rr_ExpenseExampleYear03

1,036

Lowest Quarterly Return, Label

rr_ExpenseExampleYear10

rr_AnnualReturn2010

rr_AnnualReturn2012

rr_AnnualReturn2014

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.59%

rr_LowestQuarterlyReturnLabel

Lowest Quarterly Return: Third Quarter 2014, -5.86%

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2014

rr_AverageAnnualReturnYear05

1.25%

rr_AverageAnnualReturnInceptionDate

Feb. 01, 2008

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear05

(0.48%)

rr_AverageAnnualReturnInceptionDate

Feb. 01, 2008

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear05

0.54%

rr_AverageAnnualReturnInceptionDate

Feb. 01, 2008

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

rr_RiskReturnAbstract

rr_MaximumDeferredSalesChargeOverOther

rr_ManagementFeesOverAssets

0.60%

rr_FeeWaiverOrReimbursementOverAssets

1.36%

^[9]

rr_ExpenseExampleYear01

284

rr_ExpenseExampleYear05

1,541

rr_ExpenseExampleNoRedemptionYear01

184

rr_ExpenseExampleNoRedemptionYear05

1,541

Life of Fund / Life of Class N

rr_AverageAnnualReturnYear01

(5.54%)

rr_AverageAnnualReturnSinceInception

2.43%

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

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_RedemptionFee

none

rr_DistributionAndService12b1FeesOverAssets

none

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

rr_ExpensesOverAssets

2.24%

rr_NetExpensesOverAssets

0.81%

rr_ExpenseExampleYear03

562

rr_ExpenseExampleYear10

2,463

rr_AverageAnnualReturnYear05

2.44%

rr_AverageAnnualReturnInceptionDate

Feb. 01, 2008

Objective, Primary [Text Block]

rr_RiskReturnAbstract

rr_ObjectivePrimaryTextBlock

The Fund seeks high total investment return through a combination of current income and capital appreciation.

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 57 of the Prospectus and on page 113 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

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)

rr_ExpenseExampleHeading

Example

rr_ExpenseExampleByYearCaption

If shares are redeemed:

rr_PortfolioTurnoverHeading

Portfolio Turnover

rr_PortfolioTurnoverRate

19.00%

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 investment grade fixed-income securities (for example, bonds and other investments that the Adviser believes have similar economic characteristics, such as notes, debentures and loans). "Investment grade" securities are those securities that are rated in one of the top four categories at the time of purchase by at least one of the three major rating agencies — Moody's Investors Service, Inc. ("Moody's"), Fitch Investor Services, Inc. ("Fitch") or Standard & Poor's Ratings Group ("S&P") or, if unrated, are determined by the Adviser to be of comparable quality. Although the Fund invests primarily in investment grade fixed-income securities, it may invest up to 10% of its assets in below investment grade fixed-income securities (also known as "junk bonds"). There is no minimum rating for the securities in which the Fund may invest. The Fund may invest in fixed-income securities of any maturity. The Fund has the flexibility to invest up to 10% of its assets in equity securities (such as common stocks, preferred stocks and investment companies), but will limit its investments in common stocks to 5% of its assets.

In deciding which securities to buy and sell, the Adviser will consider, among other things, the financial strength of the issuer, current interest rates, current valuations, the Adviser's expectations regarding future changes in interest rates and comparisons of the level of risk associated with particular investments with the Adviser's expectations concerning the potential return of those investments.

Three themes typically drive the Fund's investment approach. First, the Adviser generally seeks fixed-income securities of issuers whose credit profiles it believes are improving. Second, the Fund may invest significantly in securities the prices of which the Adviser believes are more sensitive to events related to the underlying issuer than to changes in general interest rates or overall market default rates. The Adviser believes that the Fund may generate positive returns by having a portion of the Fund's assets invested in non-market-related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, the Adviser analyzes different sectors of the economy and differences in the yields ("spreads") of various fixed-income securities in an effort to find securities that it believes may produce attractive returns for the Fund in comparison to their risk. The Adviser generally prefers securities that are protected against calls (early redemption by the issuer).

In connection with its principal investment strategies, the Fund may also invest any portion of its assets in securities of Canadian issuers and up to 20% of its assets in securities of other foreign issuers, including emerging markets securities. The Fund may also invest in obligations of supranational entities without limit (e.g., the World Bank), corporate securities, U.S. government securities, commercial paper, zero-coupon securities, mortgage-backed securities, including mortgage dollar rolls, stripped mortgage-backed securities and collateralized mortgage obligations and other asset-backed securities, when-issued securities, convertible securities, securities issued pursuant to Rule 144 under the Securities Act of 1933 ("Rule 144A securities") and structured notes. The Fund may also engage in foreign currency hedging transactions and swap transactions (including credit default swaps) for hedging or investment purposes. The Adviser may elect not to hedge currency risk, which may cause the Fund to incur losses that would not have been incurred had the risk been hedged. Except as provided above, the Fund is not limited in the percentage of its assets that it may invest in these instruments.