Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Feb. 28, 2012
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	MainStay Global High Income Fund
Investment Objective, Heading	rr_ObjectiveHeading	Investment Objective
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The Fund seeks maximum current income by investing in high-yield debt securities of non-U.S. issuers.
Investment Objective, Secondary	rr_ObjectiveSecondaryTextBlock	Capital appreciation is a secondary objective.
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 65% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	65.00%
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 in securities rated below investment grade at levels at least equal to the percentage of below investment grade debt found in the Fund's primary benchmark. Below investment grade securities are generally securities that receive low ratings from independent rating agencies, such as rated lower than BBB by Standard & Poor's and Baa3 by Moody's Investor Service, Inc., or if unrated, are deemed to be of comparable quality by the Fund's Subadvisor, MacKay Shields LLC. Some securities 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 lower rating for purposes of determining the security's credit quality. Normally, the Fund will invest a significant amount of its assets (at least 40%, unless the Subadvisor deems market conditions to be unfavorable, in which case the Fund will invest at least 30%) in securities issued by governments, their agencies and authorities, and corporations that are located in at least three different foreign countries. The Fund principally invests in countries that are considered emerging markets, but may invest in countries with established economies that the Subadvisor believes present favorable conditions. Some of the foreign securities in which the Fund invests may be denominated in foreign currency. The Fund's principal investments include Yankee (dollar-denominated) debt securities, Brady Bonds, variable rate notes, mortgage-related and asset-backed securities and mortgage dollar rolls. The Fund may also invest in derivative instruments, such as floaters, including inverse floaters, forward commitments, futures, options and swaps agreements to try to enhance returns or reduce the risk of loss of (hedge) certain of its holdings. The Fund may invest up to 15% of its total assets in swaps, including credit default swaps. The Fund is "non-diversified" which means that it may invest a greater percentage of its assets than other funds in a particular issuer. The Fund may buy and sell currency on a spot basis, buy foreign currency options, and enter into foreign currency forward contracts. These techniques may be used for any legally permissible purpose, including to increase the Fund's return. Investment Process: The Subadvisor identifies investment opportunities by beginning with country selection, then assessing local currencies for upside potential and downside risk and finally, evaluating specific securities based on the financial condition and competitiveness of the issuer. The Subadvisor considers factors such as prospects for a country's political stability, currency exchange rates, interest rates, inflation, relative economic growth and governmental policies. 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 foreign economies and meaningful changes in the issuer's financial condition 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. 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. Emerging Markets Risk: The risks related to investing in foreign securities are generally greater with respect to securities of companies that conduct their business activities in emerging markets or whose securities are traded principally in emerging markets. The risks of investing in emerging markets include the risks of illiquidity, increased price volatility, smaller market capitalizations, less government regulation, less extensive and less frequent accounting, financial and other reporting requirements, risk of loss resulting from problems in share registration and custody, substantial economic and political disruptions and the nationalization of foreign deposits or assets. 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.    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. 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. 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. 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. Non-Diversification Risk: Because the Fund is "non-diversified," it may be more susceptible than diversified funds to risks associated with an individual issuer, and to single economic, political or regulatory occurrences.
Risk, Lose Money	rr_RiskLoseMoney	Before considering an investment in the Fund, you should understand that you could lose money.
Risk, Nondiversified Status	rr_RiskNondiversifiedStatus	Because the Fund is "non-diversified," it may be more susceptible than diversified funds to risks associated with an individual issuer, and to single economic, political or regulatory occurrences.
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 JPMorgan EMBI Global Diversified Index as its primary benchmark. The JPMorgan EMBI Global Diversified Index is a market capitalization weighted, total return index tracking the traded market for U.S. dollar-denominated Brady Bonds, Eurobonds, traded loans and local market debt instruments issued by sovereign and quasi-sovereign entities. Performance data for the classes varies based on differences in their fee and expense structures. Class I shares were first offered to the public on August 31, 2007. Performance figures for Class I shares include the historical performance of Class A shares through August 30, 2007. Performance figures for Investor Class shares, which were first offered on February 28, 2008, include the historical performance of Class A shares through February 27, 2008. 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.
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    13.07 % Worst Quarter    4Q/08    -8.94 %
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 Global High Income Fund (Prospectus Summary) | MainStay Global High Income Fund | JPMorgan EMBI Global Diversified Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	JPMorgan EMBI Global Diversified Index (reflects no deductions for fees, expenses, or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	7.35%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	7.87%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	10.62%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	0.72%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.35%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.32%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	578
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	849
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,141
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,969
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Investor Class Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(0.69%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.86%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	10.44%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	0.72%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.25%
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	(0.57%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.96%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	10.49%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	0.72%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.35%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.07%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	710
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	949
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,314
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,208
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	210
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	649
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,114
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,208
Annual Return 2002	rr_AnnualReturn2002	10.33%
Annual Return 2003	rr_AnnualReturn2003	30.69%
Annual Return 2004	rr_AnnualReturn2004	12.00%
Annual Return 2005	rr_AnnualReturn2005	9.86%
Annual Return 2006	rr_AnnualReturn2006	10.31%
Annual Return 2007	rr_AnnualReturn2007	3.48%
Annual Return 2008	rr_AnnualReturn2008	(17.29%)
Annual Return 2009	rr_AnnualReturn2009	34.38%
Annual Return 2010	rr_AnnualReturn2010	12.86%
Annual Return 2011	rr_AnnualReturn2011	3.29%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	13.07%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(8.94%)
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class B Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	(1.54%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.73%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	10.13%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	(3.52%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.49%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	7.61%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	(0.57%)
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.63%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	7.35%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	0.72%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.35%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.07%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	310
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	649
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,114
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,400
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	210
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	649
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,114
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,400
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class C Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	2.32%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	6.05%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	10.13%
MainStay Global High Income Fund (Prospectus Summary) | MainStay Global High Income 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	0.72%	[2]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.25%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.97%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	99
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	309
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	536
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,190
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class I Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	4.37%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	7.22%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	11.28%

[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: 0.70% on assets up to $500 million and 0.65% on assets in excess of $500 million, 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.