Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Feb. 28, 2012
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	MainStay Flexible Bond Opportunities Fund
Investment Objective, Heading	rr_ObjectiveHeading	Investment Objective
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The Fund seeks current income and total return by investing primarily in domestic and foreign debt securities.
Expense, Heading	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense, Narrative	rr_ExpenseNarrativeTextBlock	The table below 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 MainStay Funds. This amount may vary depending on the MainStay Fund in which you invest. More information about these and other discounts is available from your financial professional and in the "Information on Sales Charges" section starting on page 94 of the Prospectus and in the "Alternative Sales Arrangements" section on page 104 of the Statement of Additional Information.
Shareholder Fees, Caption	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses, Caption	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover, Heading	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 26% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	26.00%
Expense Breakpoint, Discounts	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 MainStay Funds.
Expense Breakpoint, Minimum Investment Required Amount	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	50,000
Expense Example, Heading	rr_ExpenseExampleHeading	Example
Expense Example, Narrative	rr_ExpenseExampleNarrativeTextBlock	The 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 as indicated with respect to Class B and Class C shares). The Example reflects Class B shares converting into Investor Class shares in years 9-10; fees could be lower if you are eligible to convert to Class A shares instead. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same.
Expense Example, By Year, Caption	rr_ExpenseExampleByYearCaption	Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Investment Strategy, Heading	rr_StrategyHeading	Principal Investment Strategies
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	The Fund, under normal circumstances, invests at least 80% of its assets (net assets plus any borrowings for investment purposes) in a diversified portfolio of debt or debt-related securities such as: debt or debt-related securities issued or guaranteed by the U.S. or foreign governments, their agencies or instrumentalities; obligations of international or supranational entities; debt or debt-related securities issued by U.S. or foreign corporate entities; zero coupon bonds; municipal bonds; mortgage-related and other asset-backed securities; loan participation interests; convertible bonds; and variable or floating rate debt securities. The securities may be denominated in U.S. or foreign currencies, and may have fixed, variable, floating or inverse floating rates of interest. Maturities of the securities held by the Fund will vary. The Fund may invest up to 20% of its net assets in equity securities. The Fund may invest without limitation in securities of foreign issuers. The Fund may take long and short positions. The Fund's long positions, either direct long positions or through credit default swaps or total return swaps, may aggregate up to 120% of the Fund's net assets. The Fund's short positions, either direct short positions or through credit default swaps or total return swaps, may aggregate up to 20% of the Fund's net assets. The proceeds from the Fund's short positions may be used to purchase all or a portion of the additional long positions. The long and short positions held by the Fund may vary over time as market opportunities develop. Short sales are intended to allow the Fund to earn returns on securities that MacKay Shields LLC, the Fund's Subadvisor, believes will underperform the benchmark index and may allow the Fund to maintain additional long positions. The Fund may invest in derivatives, such as futures, options, forward commitments and swap agreements to try to enhance returns or reduce the risk of loss of (hedge) certain of its holdings or manage duration. The Fund may invest up to 15% of its total assets in swaps. Investment Process: The Subadvisor seeks to identify investment opportunities based on the financial condition and competitiveness of individual companies and, in the process, utilizes fundamental economic cycle analysis, and considers credit quality and interest rate trends. The Fund invests in various bond market sectors (U.S. government including mortgage-related and asset-backed securities, foreign government, U.S. corporate and foreign corporate, including below investment grade or non-investment grade securities in each of these sectors). The Subadvisor allocates the Fund's investments among the various bond market sectors based on current and projected economic and market conditions. The Fund's principal investments also may include debt securities that are rated below investment grade by an independent rating agency, such as Standard & Poor's or Moody's Investor Service Inc. or, if unrated, determined by the Subadvisor to be of comparable quality. Some securities that are rated below investment grade by independent rating agencies are commonly referred to as "junk bonds." If independent rating agencies assign different ratings to the same security, the Fund will use the higher rating for purposes of determining the security's credit quality. The Fund's investments also include floaters, variable rate notes, when-issued securities and forward commitments. The Fund may enter into mortgage dollar roll transactions, invest in to-be-announced ("TBA") securities, buy and sell currency on a spot basis, buy foreign currency options and may enter into foreign currency forward contracts. The Subadvisor may sell a security if it no longer believes the security will contribute to meeting the investment objective of the Fund. In considering whether to sell a security, the Subadvisor may evaluate, among other things, the condition of the domestic and foreign economies, and meaningful changes in the issuer's financial condition, including changes in the issuer's credit risk and competitiveness.
Risk, Heading	rr_RiskHeading	Principal Risks
Risk, Narrative	rr_RiskNarrativeTextBlock	Loss of Money Risk: Before considering an investment in the Fund, you should understand that you could lose money. Market Changes Risk: The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests, which could cause the Fund to underperform other funds with similar objectives. From time to time, markets may experience periods of acute stress that may result in increased volatility. Such market conditions tend to add significantly to the risk of short-term volatility in the net asset value of the Fund's shares. Management Risk: The investment strategies, practices and risk analysis used by the Fund's Subadvisor may not produce the desired results. Debt Securities Risk: The risks of investing in debt securities include (without limitation): (i) credit risk, i.e., the issuer may not repay the loan created by the issuance of that debt security; (ii) maturity risk, i.e., a debt security with a longer maturity may fluctuate in value more than one with a shorter maturity; (iii) market risk, i.e., low demand for debt securities may negatively impact their price; (iv) interest rate risk, i.e., when interest rates go up, the value of a debt security goes down, and when interest rates go down, the value of a debt security goes up; (v) selection risk, i.e., the securities selected by the Subadvisor may underperform the market or other securities selected by other funds; and (vi) call risk, i.e., during a period of falling interest rates, the issuer may redeem a security by repaying it early, which may reduce the Fund's income, if the proceeds are reinvested at lower interest rates. Additional risks associated with an investment in the Fund include the following: (i) not all U.S. government securities are insured or guaranteed by the U.S. government-some are backed only by the issuing agency, which must rely on its own resources to repay the debt; and (ii) the Fund's yield will fluctuate with changes in short-term interest rates.    Short Selling Risk: If a security sold short increases in price, the Fund may have to cover its short position at a higher price than the short sale price, resulting in a loss. The Fund may have substantial short positions and must borrow those securities to make delivery to the buyer. The Fund may not be able to borrow a security that it needs to deliver or it may not be able to close out a short position at an acceptable price and may have to sell related long positions before it had intended to do so. Thus, the Fund may not be able to successfully implement its short sale strategy due to limited availability of desired securities or for other reasons. The Fund also may be required to pay a premium and other transaction costs, which would increase the cost of the security sold short. The amount of any gain will be decreased, and the amount of any loss increased, by the amount of the premium, dividends, interest or expenses the Fund may be required to pay in connection with the short sale. Until the Fund replaces a borrowed security, it is required to maintain a segregated account of cash or liquid assets with the Fund's custodian to cover the Fund's short position. Generally, securities held in a segregated account cannot be sold unless they are replaced with other liquid assets. The Fund's ability to access the pledged collateral may also be impaired in the event the broker fails to comply with the terms of the contract. In such instances the Fund may not be able to substitute or sell the pledged collateral. Additionally, the Fund must maintain sufficient liquid assets (less any additional collateral pledged to the broker), marked-to-market daily, to cover the short sale obligations. This may limit the Fund's investment flexibility, as well as its ability to meet redemption requests or other current obligations. Because losses on short sales arise from increases in the value of the security sold short, such losses are theoretically unlimited. By contrast, a loss on a long position arises from decreases in the value of the security and is limited by the fact that a security's value cannot go below zero. By investing the proceeds received from selling securities short, the Fund could be deemed to be employing a form of leverage, which creates special risks. The use of leverage may increase the Fund's exposure to long positions and make any change in the Fund's net asset value greater than it would be without the use of leverage. This could result in increased volatility of returns. There is no guarantee that the Fund will leverage its portfolio, or if it does, that the Fund's leveraging strategy will be successful or that it will produce a higher return on an investment. Regulatory authorities in the U.S. or other countries may prohibit or restrict the ability of the Fund to fully implement its short-selling strategy, either generally or with respect to certain industries or countries, which may impact the Fund's ability to fully implement its investment strategies. Derivatives Risk: Derivatives are investments whose value depends on (or is derived from) the value of an underlying instrument, such as a security, asset, reference rate or index. Derivative strategies often involve leverage, which may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying instrument. Derivatives may be difficult to sell, unwind or value. Derivatives may also be subject to counterparty risk, which is the risk that the counterparty (the party on the other side of the transaction) on a derivative transaction will be unable to honor its contractual obligations to the Fund. Swap transactions tend to shift the Fund's investment exposure from one type of investment to another, and therefore entail the risk that a party will default on its payment obligations to the Fund. Futures may be more volatile than direct investments in the instrument underlying the futures, and may not correlate perfectly to the underlying instrument. Futures also may involve a small initial investment relative to the risk assumed, which could result in losses greater than if they had not been used. Due to fluctuations in the price of the underlying security, the Fund may not be able to profitably exercise an option and may lose its entire investment in an option. Forward commitments entail the risk that the instrument may be worth less when it is issued or received than the price the Fund agreed to pay when it made the commitment. The use of foreign currency forwards may result in currency exchange losses due to fluctuations in currency exchange rates or an imperfect correlation between portfolio holdings denominated in a particular currency and the forward contracts entered into by the Fund. High-Yield Securities Risk: Investments in high-yield securities (commonly referred to as "junk bonds") are sometimes considered speculative because they present a greater risk of loss than higher quality securities. Such securities may, under certain circumstances, be less liquid than higher rated securities. These securities pay investors a premium (a high interest rate or yield) because of the increased risk of loss. These securities can also be subject to greater price volatility. In times of unusual or adverse market, economic or political conditions, these securities may experience higher than normal default rates. Floaters and Variable Rate Notes Risk: Floaters and variable rate notes provide for a periodic adjustment in the interest rate paid on the securities. The rate adjustment intervals may be regular and range from daily up to annually, or may be based on an event, such as a change in the prime rate. Floating and variable rate notes may be subject to greater liquidity risk than other debt securities, meaning that there may be limitations on the Fund's ability to sell the securities at any given time. Securities with floating interest rates generally are less sensitive to interest rate changes, but may decline in value if their interest rates do not rise as much or as fast as interest rates in general. Such securities also may lose value. Mortgage Dollar Roll Transaction Risk: Mortgage dollar roll transactions are subject to certain risks, including the risk that securities returned to the Fund at the end of the roll, while substantially similar, may be inferior to what was initially sold to the counterparty. Mortgage-Backed/Asset-Backed Securities Risk: Prepayment risk is associated with mortgage-backed and asset-backed securities. If interest rates fall, the underlying debt may be repaid ahead of schedule, reducing the value of the Fund's investments. If interest rates rise, there may be fewer prepayments, which would cause the average bond maturity to rise, increasing the potential for the Fund to lose money. The value of these securities may be significantly affected by changes in interest rates, the market's perception of issuers, and the creditworthiness of the parties involved. The ability of the Fund to successfully utilize these instruments may depend on the ability of the Subadvisor to forecast interest rates and other economic factors correctly. These securities may have a structure that makes their reaction to interest rate changes and other factors difficult to predict, making their value highly volatile. Foreign Securities Risk: Investments in foreign securities may be riskier than investments in U.S. securities. Differences between U.S. and foreign regulatory regimes and securities markets, including less stringent investor protections and disclosure standards of some foreign markets, less liquid trading markets, as well as political and economic developments in foreign countries, may affect the value of the Fund's investments in foreign securities. Foreign securities may also subject the Fund's investments to changes in currency rates. These risks may be greater with respect to securities of companies that conduct their business activities in emerging markets or whose securities are traded principally in emerging markets. Convertible Securities Risk: Convertible securities may be subordinate to other securities. In part, the total return for a convertible security depends upon performance of the underlying stock into which it can be converted. Also, issuers of convertible securities are often not as strong financially as those issuing securities with higher credit ratings, are more likely to encounter financial difficulties and typically are more vulnerable to changes in the economy, such as a recession or a sustained period of rising interest rates, which could affect their ability to make interest and principal payments. If an issuer stops making interest and/or principal payments, the Fund could lose its entire investment. Equity Securities Risk: Investments in common stocks and other equity securities are particularly subject to the risk of changing economic, stock market, industry and company conditions and the risks inherent in the portfolio managers' ability to anticipate such changes that can adversely affect the value of the Fund's holdings. Opportunity for greater gain often comes with greater risk of loss. TBA Securities Risk: The principal risks are that the counterparty may not deliver the security as promised and/or that the value of the TBA security may decline prior to when the Fund receives the security. When-Issued Securities Risk: The principal risk of transactions involving when-issued securities is that the security will be worth less when it is issued or received than the price the Fund agreed to pay when it made the commitment.
Risk, Lose Money	rr_RiskLoseMoney	Before considering an investment in the Fund, you should understand that you could lose money.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	Past Performance
Performance, Narrative	rr_PerformanceNarrativeTextBlock	The following bar chart and tables indicate some of the risks of investing in the Fund. The bar chart shows you how the Fund's calendar year performance has varied over the last ten years. Sales loads are not reflected in the bar chart. If they were, returns would be less than those shown. The average annual total returns table shows how the Fund's average annual total returns (before and after taxes) for the one-, five- and ten-year periods compare to those of a broad-based securities market index. The Fund has selected the Barclays Capital U.S. Aggregate Bond Index as its primary benchmark. The Barclays Capital U.S. Aggregate Bond Index is a broad-based benchmark that measures the investment grade, U.S. dollar-denominated, fixed-rate taxable bond market, including Treasuries, government-related and corporate securities, mortgage-backed securities (agency fixed-rate and hybrid adjustable rate mortgage pass-throughs), asset-backed securities, and commercial mortgage-backed securities. Performance data for the classes varies based on differences in their fee and expense structures. Performance figures for Class I shares, first offered on January 2, 2004, include the historical performance of Class A shares through January 1, 2004. Performance figures for Investor Class shares, first offered on February 28, 2008, include the historical performance of Class A shares through February 27, 2008. The performance for newer share classes is adjusted for differences in fees and expenses. Unadjusted, the performance shown for the newer classes might have been lower. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Please visit mainstayinvestments.com for more recent performance information. Effective February 28, 2011, the Fund changed its investment strategies. The past performance in the bar chart and table reflect the Fund's prior investment objective and principal investments strategies.
Performance, Information Illustrates Variability of Returns	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and tables indicate some of the risks of investing in the Fund.
Performance, Availability Website Address	rr_PerformanceAvailabilityWebSiteAddress	mainstayinvestments.com
Performance, Past Does Not Indicate Future	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart, Heading	rr_BarChartHeading	Annual Returns, Class B Shares (by calendar year 2002-2011)
Bar Chart, Narrative	rr_BarChartNarrativeTextBlock	The bar chart shows you how the Fund's calendar year performance has varied over the last ten years. Sales loads are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart, Does Not Reflect Sales Loads	rr_BarChartDoesNotReflectSalesLoads	Sales loads are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart, Closing	rr_BarChartClosingTextBlock	Best Quarter     3Q/09     9.93 % Worst Quarter    4Q/08    -7.60 %
Index No Deduction for Fees, Expenses, Taxes	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deductions 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	Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns are not relevant if you hold your shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table, One Class of after Tax Shown	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns shown are for Class B shares. After-tax returns for the other share classes may vary.
Performance Table, Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	In some cases, the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of shares at the end of the measurement period.
Performance Table, Closing	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. In some cases, the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of shares at the end of the measurement period. Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns are not relevant if you hold your shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns shown are for Class B shares. After-tax returns for the other share classes may vary.
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns (for the periods ended December 31, 2011)
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Barclays Capital U.S. Aggregate Bond Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Barclays Capital U.S. Aggregate Bond Index (reflects no deductions for fees, expenses, or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	7.84%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	6.50%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	5.78%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Investor Class
Risk Return [Abstract]	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 the lesser of the original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none	[1]
Management Fees (as an annual percentage of the Fund's average daily net assets)	rr_ManagementFeesOverAssets	0.62%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Interest Expense on Securities Sold Short	rr_Component1OtherExpensesOverAssets	0.14%
Broker Fees and Charges on Short Sales	rr_Component2OtherExpensesOverAssets	0.04%
Remainder of Other Expenses	rr_Component3OtherExpensesOverAssets	0.37%
Total Other Expenses	rr_OtherExpensesOverAssets	0.55%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.42%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	588
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	879
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,191
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,075
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Investor Class Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(3.39%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.36%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	6.16%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Class A
Risk Return [Abstract]	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 the lesser of the original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none	[1]
Management Fees (as an annual percentage of the Fund's average daily net assets)	rr_ManagementFeesOverAssets	0.62%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Interest Expense on Securities Sold Short	rr_Component1OtherExpensesOverAssets	0.15%
Broker Fees and Charges on Short Sales	rr_Component2OtherExpensesOverAssets	0.04%
Remainder of Other Expenses	rr_Component3OtherExpensesOverAssets	0.16%
Total Other Expenses	rr_OtherExpensesOverAssets	0.35%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.22%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	569
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	820
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,090
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,861
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class A Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(3.18%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.48%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	6.23%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Class B
Risk Return [Abstract]	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 the lesser of the original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOfferingPrice	5.00%
Management Fees (as an annual percentage of the Fund's average daily net assets)	rr_ManagementFeesOverAssets	0.62%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Interest Expense on Securities Sold Short	rr_Component1OtherExpensesOverAssets	0.13%
Broker Fees and Charges on Short Sales	rr_Component2OtherExpensesOverAssets	0.04%
Remainder of Other Expenses	rr_Component3OtherExpensesOverAssets	0.37%
Total Other Expenses	rr_OtherExpensesOverAssets	0.54%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.16%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	719
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	976
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,359
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,305
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	219
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	676
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,159
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,305
Annual Return 2002	rr_AnnualReturn2002	3.99%
Annual Return 2003	rr_AnnualReturn2003	19.10%
Annual Return 2004	rr_AnnualReturn2004	6.96%
Annual Return 2005	rr_AnnualReturn2005	0.10%
Annual Return 2006	rr_AnnualReturn2006	6.72%
Annual Return 2007	rr_AnnualReturn2007	3.82%
Annual Return 2008	rr_AnnualReturn2008	(13.84%)
Annual Return 2009	rr_AnnualReturn2009	26.17%
Annual Return 2010	rr_AnnualReturn2010	10.15%
Annual Return 2011	rr_AnnualReturn2011	0.43%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	9.93%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(7.60%)
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class B Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(4.40%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.22%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	5.86%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Class B | After Taxes on Distributions
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class B Return After Taxes on Distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(5.76%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.30%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	4.03%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Class B | After Taxes on Distributions and Sales
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class B Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(2.84%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.46%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	3.97%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Class C
Risk Return [Abstract]	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 the lesser of the original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOfferingPrice	1.00%
Management Fees (as an annual percentage of the Fund's average daily net assets)	rr_ManagementFeesOverAssets	0.62%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Interest Expense on Securities Sold Short	rr_Component1OtherExpensesOverAssets	0.16%
Broker Fees and Charges on Short Sales	rr_Component2OtherExpensesOverAssets	0.04%
Remainder of Other Expenses	rr_Component3OtherExpensesOverAssets	0.37%
Total Other Expenses	rr_OtherExpensesOverAssets	0.57%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.19%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	322
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	685
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,175
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,524
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	222
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	685
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,175
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,524
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class C Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(0.54%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.52%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	5.85%
MainStay Flexible Bond Opportunities Fund (Prospectus Summary) | MainStay Flexible Bond Opportunities Fund | Class I
Risk Return [Abstract]	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 the lesser of the original offering price or redemption proceeds)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management Fees (as an annual percentage of the Fund's average daily net assets)	rr_ManagementFeesOverAssets	0.62%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Interest Expense on Securities Sold Short	rr_Component1OtherExpensesOverAssets	0.20%
Broker Fees and Charges on Short Sales	rr_Component2OtherExpensesOverAssets	0.04%
Remainder of Other Expenses	rr_Component3OtherExpensesOverAssets	0.16%
Total Other Expenses	rr_OtherExpensesOverAssets	0.40%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.02%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	104
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	325
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	563
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,248
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class I Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	1.63%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.78%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	7.04%

[1] A contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within one year of the date of purchase on shares that were purchased without an initial sales charge.

[2] The management fee is as follows: 0.60% on assets up to $500 million; 0.55% on assets from $500 million up to $1 billion; and 0.50% on assets in excess of $1 billion, plus a fee for fund accounting services previously provided by New York Life Investment Management LLC ("New York Life Investments") under a separate fund accounting agreement. This addition to the management fee amounted to 0.02% of the Fund's average daily net assets, but did not result in a net increase in Total Annual Fund Operating Expenses.