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Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund  
Risk/Return: oef_RiskReturnAbstract  
Risk/Return [Heading] oef_RiskReturnHeading NYLI MacKay High Yield Corporate Bond Fund
Objective [Heading] oef_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] oef_ObjectivePrimaryTextBlock

The Fund seeks maximum current income through investment in a diversified portfolio of high-yield debt securities. Capital appreciation is a secondary objective.
Expense Heading [Optional Text] oef_ExpenseHeading Fees and Expenses of the Fund
Expense Narrative [Text Block] oef_ExpenseNarrativeTextBlock

The table below describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below. 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 Fund. In addition, different financial intermediary firms and financial professionals may impose different sales loads and waivers. More information about these and other discounts or waivers is available from your financial professional, in the "Information on Sales Charges" section starting on page 202 of the Prospectus and Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts, and in the "Alternative Sales Arrangements" section on page 150 of the Statement of Additional Information.

Shareholder Fees Caption [Optional Text] oef_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Optional Text] oef_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] oef_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] oef_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 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 34% of the average value of its portfolio.

Portfolio Turnover, Rate oef_PortfolioTurnoverRate 34.00%
Expense Breakpoint Discounts [Text] oef_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 Fund.
Expense Breakpoint, Minimum Investment Required [Amount] oef_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 100,000
Expense Example [Heading] oef_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] oef_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 whether or not you redeem all of your shares at the end of those periods (except as indicated with respect to Class C shares). The Example reflects Class C shares converting into Investor Class shares in years 9-10; expenses 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. The Example reflects the contractual fee waiver and/or expense reimbursement arrangement, if applicable, for the current duration of the arrangement only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example by, Year, Caption [Text] oef_ExpenseExampleByYearCaption Assuming redemption at end of period
Expense Example, No Redemption, By Year, Caption [Text] oef_ExpenseExampleNoRedemptionByYearCaption Assuming no redemption
Strategy [Heading] oef_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] oef_StrategyNarrativeTextBlock

The Fund, under normal circumstances, invests at least 80% of its assets (net assets plus any borrowings for investment purposes) in high-yield corporate debt securities, including all types of high-yield domestic and foreign corporate debt securities that are rated below investment grade by a nationally recognized statistical rating organization (“NRSRO”) or that are unrated but are considered to be of comparable quality by MacKay Shields LLC, the Fund's Subadvisor. Corporate debt securities are bonds and other debt securities, including preferred stock, convertible corporate securities and loans and loan participations, issued by corporations and other business structures. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. An issuer of a security is considered to be a U.S. or foreign issuer based on the issuer's "country of risk" (or similar designation) as determined by a third-party such as Bloomberg.

Securities that are rated below investment grade by NRSROs (such as securities rated lower than BBB- and Baa3) are commonly referred to as “high-yield securities” or "junk bonds." If NRSROs assign different ratings to the same security for purposes of determining the security's credit quality, the Fund will use the middle rating when three NRSROs rate the security. For securities where only two NRSROs rate the security, the Fund will use the higher rating. If only one rating is available for a security, the Fund will use that rating.

The Fund's high-yield investments may also include convertible corporate securities, loans and loan participation interests. The Fund may invest up to 20% of its net assets in common stocks and other equity-related securities.

The Fund may hold cash or invest in short-term instruments during times when the Subadvisor is unable to identify attractive high-yield securities.

The Fund may invest in derivatives, such as futures, options and swap agreements to seek enhanced returns or to reduce the risk of loss by hedging certain of its holdings.

In times of unusual or adverse market, economic or political conditions, the Fund may invest without limit in investment grade securities and may invest in U.S. government securities or other high quality money market instruments. Periods of unusual or adverse market, economic or political conditions may exist in some cases, for up to a year or longer. To the extent the Fund is invested in cash, investment grade debt or other high quality instruments, the yield on these investments tends to be lower than the yield on other investments normally purchased by the Fund. Although investing heavily in these investments may help to preserve the Fund's assets, it may not be consistent with the Fund's primary investment objective and may limit the Fund's ability to achieve a high level of income.

Investment Process: The Subadvisor seeks to identify investment opportunities by analyzing individual companies and evaluating each company's competitive position, financial condition, and business prospects. The Fund invests in companies in which the Subadvisor has judged that there is sufficient asset coverage—that is, the Subadvisor's subjective appraisal of a company's value compared to the value of its debt, with the intent of maximizing risk-adjusted income and returns.

The Subadvisor may sell a security if it believes the security will no longer contribute to meeting the investment objectives of the Fund. In considering whether to sell a security, the Subadvisor may evaluate, among other things, the price of the security and meaningful changes in the issuer's financial condition and competitiveness.
Bar Chart and Performance Table [Heading] oef_BarChartAndPerformanceTableHeading Past Performance
Performance Narrative [Text Block] oef_PerformanceNarrativeTextBlock

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns compare with those of a broad measure of market performance and an additional index over time. Sales loads, if any, are not reflected in the bar chart. If they were, returns would be less than those shown. The Fund has selected the Bloomberg U.S. Aggregate Bond Index to represent a broad measure of market performance. The table also includes the average annual returns of the ICE BofA U.S. High Yield Constrained Index, which is generally representative of the market sectors or types of investments in which the Fund invests.

Index returns reflect no deductions for fees, expenses or taxes, except for foreign withholding taxes where applicable.

Performance data for the classes varies based on differences in their fee and expense structures. Performance data is not shown for classes with less than one calendar year of performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Please visit nylim.com/funds for more recent performance information.
Performance One Year or Less [Text] oef_PerformanceOneYearOrLess Performance data is not shown for classes with less than one calendar year of performance.
Performance Availability Website Address [Text] oef_PerformanceAvailabilityWebSiteAddress nylim.com/funds
Performance Past Does Not Indicate Future [Text] oef_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading] oef_BarChartHeading Annual Returns, Class I Shares(by calendar year 2016-2025)
Bar Chart Does Not Reflect Sales Loads [Text] oef_BarChartDoesNotReflectSalesLoads Sales loads, if any, are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart Closing [Text Block] oef_BarChartClosingTextBlock
   

Best Quarter

 

2020, Q2

9.50

%

Worst Quarter

 

2020, Q1

-12.56

%
Performance Table Heading oef_PerformanceTableHeading Average Annual Total Returns (for the periods ended December 31, 2025)
Performance Table Uses Highest Federal Rate oef_PerformanceTableUsesHighestFederalRate After-tax returns are calculated using the highest individual federal marginal income tax rates in effect at the time of each distribution or capital gain or upon the sale of Fund shares, and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred oef_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 [Text] oef_PerformanceTableOneClassOfAfterTaxShown After-tax returns shown are for Class I shares. After-tax returns for the other share classes may vary.
Performance Table Explanation after Tax Higher oef_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 Narrative oef_PerformanceTableNarrativeTextBlock After-tax returns are calculated using the highest individual federal marginal income tax rates in effect at the time of each distribution or capital gain or upon the sale of Fund shares, 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 I shares. After-tax returns for the other share classes may vary.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Principal Risks  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock
Principal Risks

You can lose money by investing in the Fund. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. The investments selected by the Subadvisor may underperform the market in which the Fund invests or other investments. The Fund may receive large purchase or redemption orders which may have adverse effects on performance if the Fund were required to sell securities, invest cash or hold a relatively large amount of cash at times when it would not otherwise do so.

The principal risks of investing in the Fund are summarized below. The relative significance of each principal risk summarized below may change over time.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Risk Lose Money [Member]  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock You can lose money by investing in the Fund.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Risk Not Insured Depository Institution [Member]  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Market Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Market Risk: Changes in markets may cause the value of investments to fluctuate, which could cause the Fund to underperform other funds with similar investment objectives and strategies. Such changes may be rapid and unpredictable. From time to time, markets may experience periods of stress as a result of various market, economic, social and geopolitical factors (including responses to government actions or interventions), such as the imposition (or the threatened imposition) of tariffs for potentially prolonged periods that may result in: (i) increased market volatility; (ii) reduced market liquidity; and (iii) increased redemptions of shares. Certain securities may be difficult to value under such conditions, and such conditions may add significantly to the risk of volatility in the net asset value of the Fund's shares and adversely affect the Fund and its investments.

Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Portfolio Management Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Portfolio Management Risk: The investment strategies, practices and risk analyses used by the Subadvisor may not produce the desired results or expected returns.

Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Yield Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Yield Risk: There can be no guarantee that the Fund will achieve or maintain any particular level of yield.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Debt Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Debt Securities Risk: The risks of investing in debt or fixed-income securities include (without limitation): (i) credit risk, e.g., the issuer or guarantor of a debt security may be unable or unwilling (or be perceived by market participants, rating agencies, pricing services or otherwise as unable or unwilling) to make timely principal and/or interest payments or otherwise honor its obligations, or changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may affect the value of the Fund’s investments; (ii) maturity risk, e.g., a debt security with a

longer maturity may fluctuate in value more than one with a shorter maturity; (iii) market risk, e.g., low demand for debt securities may negatively impact their price; (iv) interest rate risk, e.g., when interest rates go up, the value of a debt security generally goes down, and when interest rates go down, the value of a debt security generally goes up (long-term debt securities are generally more susceptible to interest rate risk than short-term debt securities); and (v) call or prepayment risk, e.g., 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.

Interest rate risk is the risk that the value of the Fund’s investments in fixed-income or debt securities will change because of changes in interest rates. There is a risk that interest rates across the financial system may change, possibly significantly and/or rapidly. Changes in interest rates (or the expectation of such changes) or a lack of market participants may lead to decreased liquidity and increased volatility in the fixed-income or debt markets, making it more difficult for the Fund to sell its fixed-income or debt holdings. Decreased liquidity in the fixed-income or debt markets also may make it more difficult to value some or all of the Fund’s fixed-income or debt holdings. For most fixed-income investments, when market interest rates fall, prices of previously-issued fixed-rate debt securities rise. However, when market interest rates fall, prices of certain variable and fixed-rate debt securities may be adversely affected (i.e., falling interest rates bring the possibility of prepayment risk, as an instrument may be redeemed before maturity). Very low or negative interest rates may magnify interest rate risk. There is a risk that the income generated by investments may not keep pace with inflation. Actions by governments and central banking authorities can result in increases or decreases in interest rates. Periods of higher inflation could cause such authorities to raise interest rates, which may adversely affect the Fund and its investments. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from Fund performance to the extent the Fund is exposed to such interest rates and/or volatility. Other factors that may affect the value of debt securities include, but are not limited to, economic, social, political, public health, and other crises and responses by governments and companies to such crises.

Not all U.S. government debt securities are 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. The Fund's yield will fluctuate with changes in short-term interest rates.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | High-Yield Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

High-Yield Securities Risk: Investments in high-yield securities or non-investment grade securities (commonly referred to as "junk bonds") are considered speculative by certain ratings agencies because investments in such securities present a greater risk of loss than investments in 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 potential illiquidity and increased risk of loss (which may be substantial or total loss) of income and principal. 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.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Liquidity and Valuation Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Liquidity and Valuation Risk: The Fund’s investments may be illiquid at the time of purchase or liquid at the time of purchase and subsequently become illiquid due to, among other things, events relating to the issuer of the securities, market events, operational issues, economic conditions, investor perceptions or lack of market participants. The lack of an active trading market may make it difficult to sell or obtain an accurate price for a security. If market conditions or issuer specific developments make it difficult to value securities, the Fund may value these securities using more subjective methods, such as fair value pricing. In such cases, the value determined for a security could be different than the value realized upon such security's sale. As a result, an investor could pay more than the market value when buying shares or receive less than the market value when selling shares. This could affect the proceeds of any redemption or the number of shares an investor receives upon purchase. The Fund is subject to the risk that it could not meet redemption requests within the allowable time period without significant dilution of remaining investors' interests in the Fund. To meet redemption requests or to raise cash to pursue other investment opportunities, the Fund may be forced to sell securities at an unfavorable time and/or under unfavorable conditions, which may adversely affect the Fund’s performance. These risks are heightened for fixed-income instruments in a changing or volatile interest rate environment.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Loan Participation Interest Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Loan Participation Interest Risk: There may not be a readily available market for loan participation interests, which in some cases could result in the Fund disposing of such interests at a substantial discount from face value or holding such interests until maturity. In addition, the Fund may be exposed to the credit risk of the underlying corporate borrower as well as the lending institution or other participant from whom the Fund purchased the loan participation interests. The Fund may not always have direct recourse against a borrower if the borrower fails to pay scheduled principal and/or interest and may be subject to greater delays, expenses and risks than if the Fund had purchased a direct obligation of the borrower. Substantial increases in interest rates may cause an increase in loan obligation defaults.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Floating Rate Loans Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Floating Rate Loans Risk: The floating rate loans in which the Fund invests are usually rated below investment grade, or, if unrated, determined by the Subadvisor to be of comparable quality (commonly referred to as "junk bonds") and are generally considered speculative because they present a greater risk of loss, including default, than higher quality debt instruments. Moreover, such investments may, under certain circumstances, be particularly susceptible to liquidity and valuation risks. Although certain floating rate loans are collateralized, there is no guarantee that the value of the collateral will be sufficient or available to satisfy the borrower’s obligation. In times of unusual or adverse market, economic or political conditions, floating rate loans may experience higher than normal default rates. In the event of a recession or serious credit event, among other eventualities, the value of the Fund's investments in floating rate loans are more likely to decline. The secondary market for floating rate loans is limited and, thus, the Fund’s ability to sell or realize the full value of its investment in these loans to reinvest sale proceeds or to meet redemption obligations may be impaired. In addition, floating rate loans generally are subject to extended settlement periods that may be longer than seven days. As a result, the Fund may be adversely affected by selling other investments at an unfavorable time and/or under

unfavorable conditions or engaging in borrowing transactions, such as borrowing against its credit facility, to raise cash to meet redemption obligations or pursue other investment opportunities.

In certain circumstances, floating rate loans may not be deemed to be securities. As a result, the Fund may not have the protection of the anti-fraud provisions of the federal securities laws. In such cases, the Fund generally must rely on the contractual provisions in the loan agreement and common-law fraud protections under applicable state law.

Floating rate loans and other similar debt obligations that lack financial maintenance covenants or possess fewer or contingent financial maintenance covenants and other financial protections for lenders and investors (sometimes referred to as “covenant-lite” loans or obligations) are generally subject to more risk than investments that contain traditional financial maintenance covenants and financial reporting requirements.

The terms of many floating rate loans and other instruments are tied to reference rates or benchmarks such as the Secured Overnight Financing Rate (“SOFR”).

Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Convertible Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Convertible Securities Risk: Convertible securities are typically subordinate to an issuer’s other debt obligations. In part, the total return for a convertible security depends upon the 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. Certain types of convertible securities may decline in value or lose their value entirely in the event that the issuer's financial condition becomes significantly impaired. If an issuer stops making interest and/or principal payments, the Fund could lose its entire investment.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Foreign Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Foreign Securities Risk: An issuer of a security is considered to be a U.S. or foreign issuer based on the issuer’s “country of risk” (or similar designation) as determined by a third party such as Bloomberg (or another similar third party). The issuer’s “country of risk” is determined based on a number of criteria, which may change from time to time and currently include, but are not limited to, its country of domicile, the primary stock exchange on which it trades, the location from which the majority of its revenue comes, and its reporting currency.

Investments in foreign (non-U.S.) securities may be riskier than investments in U.S. securities. Foreign regulatory regimes and securities markets can have less stringent investor protections and disclosure standards and less liquid trading markets than U.S. regulatory regimes and securities markets, and can experience political, social and economic developments (such as government expropriation, excessive taxation, political or social instability, trade restrictions (including tariffs) or economic sanctions) that may affect the value of investments in foreign securities. There can also be difficulty obtaining and enforcing judgments against issuers in foreign countries. Foreign securities may also subject the Fund's investments to changes in currency rates. Changes in the value of foreign currencies may make the return on an investment increase or decrease, unrelated to the quality or performance of the investment itself. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions or developments could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell certain foreign securities or groups of foreign securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. Such sanctions may also cause a decline in the value of securities issued by the sanctioned country or companies located in or economically tied to the sanctioned country. In addition, as a result of economic sanctions and other similar governmental actions or developments, the Fund may be forced to sell or otherwise dispose of foreign investments at inopportune times or prices. The Fund may seek to hedge against its exposure to changes in the value of foreign currency, but there is no guarantee that such hedging techniques will be successful in reducing any related foreign currency valuation risk.

Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Derivatives Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

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 may be riskier than investing directly in the underlying instrument and often involve leverage, which may exaggerate a loss, potentially causing the Fund to lose more money than it originally invested and would have lost had it invested directly in the underlying instrument. For example, if the Fund is the seller of credit protection in a credit default swap, the Fund effectively adds leverage to its portfolio and is subject to the credit exposure on the full notional value of the swap. Derivatives may be difficult to sell, unwind and/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 or unwilling to honor its contractual obligations to the Fund. Futures and other derivatives may be more volatile than direct investments in the instrument underlying the contract, and may not correlate perfectly to the underlying instrument. Futures and other derivatives 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 instrument, the Fund may not be able to profitably exercise an option and may lose its entire investment in an option. To the extent that the Fund writes or sells an option, if the decline in the value of the underlying instrument is significantly below the exercise price in the case of a written put option or increase above the exercise price in the case of a written call option, the Fund could experience a substantial loss. Swaps may be subject to counterparty credit, correlation, valuation, liquidity and leveraging risks. Swap transactions tend to shift a Fund's investment exposure from one type of investment to another and may entail the risk that a party will default on its payment obligations to the Fund. Additionally, applicable regulators have adopted rules imposing certain margin requirements, including minimums on uncleared swaps, which may result in the Fund and its counterparties posting higher margin amounts for uncleared swaps. Certain standardized swaps are subject to mandatory central clearing and exchange trading. Central clearing, which interposes a central clearinghouse to each participant’s swap, and exchange trading are intended to reduce counterparty credit risk and increase liquidity but neither makes swap transactions risk-free. Derivatives may also increase the expenses of the Fund.

Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Equity Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

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 ability to anticipate such changes that can adversely affect the value of portfolio holdings.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Money Market/Short-Term Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Money Market/Short-Term Securities Risk: To the extent the Fund holds cash or invests in money market or short-term securities, the Fund may be less likely to achieve its investment objective. In addition, it is possible that the Fund's investments in these instruments could lose money.
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Private Placement and Restricted Securities Risk  
Risk/Return: oef_RiskReturnAbstract  
Risk [Text Block] oef_RiskTextBlock

Private Placement and Restricted Securities Risk: The Fund may invest in privately issued securities, including those which may be resold only in accordance with Rule 144A under the Securities Act of 1933, as amended. Securities acquired in a private placement generally are subject to strict restrictions on resale, and there may be no market or a limited market for the resale of such securities. Therefore, the Fund may be unable to dispose of such securities when it desires to do so or at the most favorable price. This potential lack of liquidity also may make it more difficult to accurately value these securities.

Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Bloomberg U.S. Aggregate Bond Index1  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel Bloomberg U.S. Aggregate Bond Index1 [1]
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.30%
Average Annual Return, Percent oef_AvgAnnlRtrPct (0.36%)
Average Annual Return, Percent oef_AvgAnnlRtrPct 2.01%
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | ICE BofA U.S. High Yield Constrained Index2  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Label [Optional Text] oef_AverageAnnualReturnLabel ICE BofA U.S. High Yield Constrained Index2 [2]
Average Annual Return, Percent oef_AvgAnnlRtrPct 8.50%
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.50%
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.44%
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class A  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 4.50%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00% [3]
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.18%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.97%
Expenses Deferred Charges [Text Block] oef_ExpensesDeferredChargesTextBlock No initial sales charge applies on investments of $1 million or more (and certain other qualified purchases referenced within “Information on Sales Charges” in the Shareholder Guide). However, a contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. For more information on contingent deferred sales charges, see “Sales Charges” in the Shareholder Guide.
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 545
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 745
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 962
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,586
Average Annual Return, Percent oef_AvgAnnlRtrPct 1.65%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.14%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.23%
Performance Inception Date oef_PerfInceptionDate Jan. 03, 1995
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | INVESTOR CLASS  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 4.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00% [3]
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.37%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.16%
Expenses Deferred Charges [Text Block] oef_ExpensesDeferredChargesTextBlock No initial sales charge applies on investments of $1 million or more (and certain other qualified purchases referenced within “Information on Sales Charges” in the Shareholder Guide). However, a contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. For more information on contingent deferred sales charges, see “Sales Charges” in the Shareholder Guide.
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 513
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 754
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 1,013
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,753
Average Annual Return, Percent oef_AvgAnnlRtrPct 2.13%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.11%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.12%
Performance Inception Date oef_PerfInceptionDate Feb. 28, 2008
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class C  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 1.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.37%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.91%
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 294
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 600
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 1,032
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 2,038
Expense Example, No Redemption, 1 Year oef_ExpenseExampleNoRedemptionYear01 194
Expense Example, No Redemption, 3 Years oef_ExpenseExampleNoRedemptionYear03 600
Expense Example, No Redemption, 5 Years oef_ExpenseExampleNoRedemptionYear05 1,032
Expense Example, No Redemption, 10 Years oef_ExpenseExampleNoRedemptionYear10 $ 2,038
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.47%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.15%
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.83%
Performance Inception Date oef_PerfInceptionDate Sep. 01, 1998
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class I  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.18%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.72%
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 74
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 230
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 401
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 894
Highest Quarterly Return, Label [Optional Text] oef_HighestQuarterlyReturnLabel Best Quarter
Highest Quarterly Return, Date oef_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return oef_BarChartHighestQuarterlyReturn 9.50%
Lowest Quarterly Return, Label [Optional Text] oef_LowestQuarterlyReturnLabel Worst Quarter
Lowest Quarterly Return, Date oef_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return oef_BarChartLowestQuarterlyReturn (12.56%)
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.70%
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.35%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.99%
Annual Return [Percent] oef_AnnlRtrPct 15.78%
Annual Return [Percent] oef_AnnlRtrPct 6.79%
Annual Return [Percent] oef_AnnlRtrPct (1.46%)
Annual Return [Percent] oef_AnnlRtrPct 12.85%
Annual Return [Percent] oef_AnnlRtrPct 5.12%
Annual Return [Percent] oef_AnnlRtrPct 5.37%
Annual Return [Percent] oef_AnnlRtrPct (7.91%)
Annual Return [Percent] oef_AnnlRtrPct 11.75%
Annual Return [Percent] oef_AnnlRtrPct 6.96%
Annual Return [Percent] oef_AnnlRtrPct 6.70%
Performance Inception Date oef_PerfInceptionDate Jan. 02, 2004
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class I | After Taxes on Distributions  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.00%
Average Annual Return, Percent oef_AvgAnnlRtrPct 2.02%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.57%
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class I | After Taxes on Distributions and Sales  
Risk/Return: oef_RiskReturnAbstract  
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.92%
Average Annual Return, Percent oef_AvgAnnlRtrPct 2.30%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.56%
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class R2  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.28%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.07%
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 109
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 340
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 590
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,306
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.33%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.99%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.61%
Performance Inception Date oef_PerfInceptionDate May 01, 2008
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class R3  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.50%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.28%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.32%
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 134
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 418
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 723
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,590
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.29%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.73%
Average Annual Return, Percent oef_AvgAnnlRtrPct 5.60%
Performance Inception Date oef_PerfInceptionDate Feb. 29, 2016
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | Class R6  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.00%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.03%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 0.57%
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 58
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 183
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 318
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 714
Average Annual Return, Percent oef_AvgAnnlRtrPct 7.10%
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.53%
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.14%
Performance Inception Date oef_PerfInceptionDate Jun. 17, 2013
Prospectus Summary | NYLI MacKay High Yield Corporate Bond Fund | SIMPLE CLASS  
Risk/Return: oef_RiskReturnAbstract  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) oef_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 0.00%
Maximum Deferred Sales Charge (as a percentage) oef_MaximumDeferredSalesChargeOverOther 0.00%
Management Fees (as a percentage of Assets) oef_ManagementFeesOverAssets 0.54% [4]
Distribution and Service (12b-1) Fees oef_DistributionAndService12b1FeesOverAssets 0.50%
Other Expenses (as a percentage of Assets): oef_OtherExpensesOverAssets 0.12%
Expenses (as a percentage of Assets) oef_ExpensesOverAssets 1.16%
Expense Example, with Redemption, 1 Year oef_ExpenseExampleYear01 $ 118
Expense Example, with Redemption, 3 Years oef_ExpenseExampleYear03 368
Expense Example, with Redemption, 5 Years oef_ExpenseExampleYear05 638
Expense Example, with Redemption, 10 Years oef_ExpenseExampleYear10 $ 1,409
Average Annual Return, Percent oef_AvgAnnlRtrPct 6.40%
Average Annual Return, Percent oef_AvgAnnlRtrPct 3.80%
Average Annual Return, Percent oef_AvgAnnlRtrPct 4.34%
Performance Inception Date oef_PerfInceptionDate Aug. 31, 2020
[1] The Bloomberg U.S. Aggregate Bond Index is a broad-based benchmark that measures the performance of 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.
[2] The ICE BofA U.S. High Yield Constrained Index is a market value-weighted index of all domestic and Yankee high-yield bonds, including deferred interest bonds and payment-in-kind securities. Issuers included in the ICE BofA U.S. High Yield Constrained Index have maturities of one year or more and have a credit rating lower than BBB-/Baa3, but are not in default. No single issuer may constitute greater than 2% of the ICE BofA U.S. High Yield Constrained Index.
[3] No initial sales charge applies on investments of $1 million or more (and certain other qualified purchases referenced within “Information on Sales Charges” in the Shareholder Guide). However, a contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. For more information on contingent deferred sales charges, see “Sales Charges” in the Shareholder Guide.
[4] The management fee is as follows: 0.60% on assets up to $500 million; 0.55% on assets from $500 million to $5 billion; 0.525% on assets from $5 billion to $7 billion; 0.50% on assets from $7 billion to $10 billion; 0.49% on assets from $10 billion to $15 billion; and 0.48% on assets over $15 billion, plus a fee for fund accounting services previously provided by New York Life Investment Management LLC under a separate fund accounting agreement. This fund accounting services fee amounted to 0.01% of the Fund's average daily net assets.