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, No Redemption, By Year, Caption [Text]

oef_ExpenseExampleNoRedemptionByYearCaption

Assuming no redemption

Strategy Narrative [Text Block]

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The Fund, under normal circumstances, invests at least 80% of its assets (net assets plus any borrowings for investment purposes) in an actively managed, diversified portfolio of U.S. infrastructure-related debt issuers and/or securities intended primarily to finance infrastructure-related activities. Fixed income securities are debt obligations and similar instruments that represent a creditor relationship with an issuer or trust and generally provide for the payment of interest (fixed, floating, or otherwise variable) and the repayment of principal, whether at maturity or over time. Infrastructure-related debt securities may include securities with special features (e.g., puts and variable or floating rates) that have price volatility characteristics similar to other debt securities.

Infrastructure-related investments include securities issued to finance any assets or projects that support the operation, function, growth or development of a community or economy. Examples of these investments include, but are not limited to, transportation assets (e.g., roads and bridges), utility assets (e.g., electric, gas and water distribution facilities and networks) and social assets (e.g., hospitals and schools).

The Fund may also invest in securities of issuers that (i) directly invest in infrastructure-related companies; (ii) operate or utilize infrastructure-related assets (e.g., airlines, automakers and technology companies); or (iii) have indirect exposure to infrastructure-related assets (e.g., suppliers of construction materials). The Fund’s Subadvisor, MacKay Shields LLC, defines an infrastructure-related issuer as an issuer that derives at least 50% of its revenues or profits from, or devotes at least 50% of its assets to, the ownership, management, development, construction, renovation, enhancement, or operation of infrastructure assets or the provision of services to companies engaged in such activities.

The Fund invests at least 60% of its assets in taxable municipal debt securities. The Fund may invest up to 20% of its assets in tax-exempt municipal debt securities. On average, the Fund will invest in municipal bonds that have a maturity of 5 years or longer.

Municipal debt securities include bonds issued by, or on behalf of, the District of Columbia, the states, the territories (including Puerto Rico, Guam and the U.S. Virgin Islands), commonwealths and possessions of the United States and their political subdivisions, and agencies, authorities and instrumentalities. All distributions by the Fund, including any distributions derived from tax-exempt municipal obligations, may be includible in taxable income for purposes of the federal alternative minimum tax. The Fund does not seek to provide income exempt from federal income tax. The Fund may invest in both taxable and tax-exempt municipal bonds.

The Fund invests in investment grade securities as rated by a nationally recognized statistical rating organization (“NRSRO”) at the time of purchase, or if unrated, determined to be of comparable quality by MacKay Shields LLC, the Fund’s Subadvisor, and invests in commercial paper only if rated in the top two highest rating categories by an NRSRO at the time of purchase, or if unrated, determined by the Subadvisor to be of comparable quality. If NRSROs assign different ratings for the same security, the Fund will use the higher rating for purposes of determining the credit quality.

The Fund's principal investments may have fixed, variable or floating interest rates and include: taxable and tax-exempt municipal debt securities; obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities; mortgage-related and asset-backed securities; certificates of deposit, time deposits and bankers' acceptances issued by U.S. banks or savings and loan associations; and debt securities issued by the United States.

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

Investment Process: The Subadvisor seeks to allocate investments primarily across the taxable fixed income market but can also utilize the tax-exempt fixed income market as well as treasuries and agencies. Allocations are based on the current economic environment, the level of absolute and relative yields, and the interest rate outlook. The Subadvisor’s investment process includes a risk analysis that gives consideration to a variety of security-specific risks, including but not limited to, environmental, social and governance (“ESG”) risks that may have a material impact on the performance of a security. In addition to proprietary research, the Subadvisor may use screening tools and, to the extent available, third-party data to identify ESG risk factors that may not have been captured through its own research. The Subadvisor’s consideration of ESG risk is weighed against other criteria and no sectors or industries are explicitly excluded from the Fund.

The Subadvisor may sell a security if it no longer believes that the security will contribute to meeting the investment objective of the Fund, which may be determined by an evaluation of economic conditions, the issuer's financial condition or relative yield and return expectations.

Bar Chart and Performance Table [Heading]

oef_BarChartAndPerformanceTableHeading

Past Performance

Performance One Year or Less [Text]

oef_PerformanceOneYearOrLess

Performance data is not shown for classes with less than one calendar year of performance.

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 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.

Performance Table Heading

oef_PerformanceTableHeading

Average Annual Total Returns (for the periods ended December 31, 2025)

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 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.

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.

Investments in the Fund are not guaranteed. While some of the Fund's investments, such as U.S. Treasury obligations, are backed by the "full faith and credit" of the U.S. government, some securities issued or guaranteed by federal agencies and U.S. government sponsored instrumentalities may not be guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government.

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.

Risk/Return:

oef_RiskReturnAbstract

Risk [Text Block]

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Portfolio Management Risk: The investment strategies, practices and risk analyses used by the Subadvisor may not produce the desired results or expected returns. The Subadvisor may give consideration to certain ESG criteria when evaluating an investment opportunity. The application of ESG criteria may result in the Fund (i) having exposure to certain securities or industry sectors that are different than the composition of the Fund's benchmark; and (ii) performing differently than other funds and strategies in its peer group that do not take into account ESG criteria or the Fund's benchmark.

Risk/Return:

oef_RiskReturnAbstract

Risk [Text Block]

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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. Investments in debt or fixed-income securities with put options may receive a lower interest rate than similar investments with a fixed-rate that cannot be redeemed before maturity. In addition, if the Fund chooses to exercise its right to put the bond back to the issuer or put provider, these investments are subject to, among other risks, the risk that the put provider will be unable or unwilling to honor the put feature (i.e., purchase the security).

Risk/Return:

oef_RiskReturnAbstract

Risk [Text Block]

oef_RiskTextBlock

Municipal Bond Risk: Municipal bond risks include the inability of the issuer to repay the obligation, the relative lack of information about certain issuers, and the possibility of future tax and legislative changes, which could affect the market for and value of municipal securities. Additional risks include:

· General Obligation Bonds Risk—timely payments depend on the issuer's credit quality, ability to raise tax revenues and ability to maintain an adequate tax base;

· Revenue Bonds (including Industrial Development Bonds) Risk—timely payments depend on the money earned by the particular facility or class of facilities, or the amount of revenues derived from another source, and may be negatively impacted by the general credit of the user of the facility;

· Private Activity Bonds Risk—municipalities and other public authorities issue private activity bonds to finance development of industrial facilities for use by a private enterprise, which is solely responsible for paying the principal and interest on the bond, and payment under these bonds depends on the private enterprise’s ability to do so;

· Moral Obligation Bonds Risk—moral obligation bonds are generally issued by special purpose public authorities of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral commitment, but not a legal obligation, of the state or municipality;

· Municipal Notes Risk—municipal notes are shorter-term municipal debt obligations that pay interest that is, in the opinion of bond counsel, generally excludable from gross income for federal income tax purposes (except that the interest may be includable in taxable income for purposes of the federal alternative minimum tax) and that have a maturity that is generally one year or less. If there is a shortfall in the anticipated proceeds, the notes may not be fully repaid and the Fund may lose money; and

· Municipal Lease Obligations Risk—in a municipal lease obligation, the issuer agrees to make payments when due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease obligation, the lease obligation is secured by the leased property. Municipal leases may pose additional risks because many leases and contracts contain “non-appropriation” clauses that provide that the governmental issuer has no obligation to make future payments under the lease or contract unless money is appropriated for this purpose by the appropriate legislative body.

Municipalities may experience political, economic and financial difficulties in an adverse economic environment. The ability of a municipal issuer to make payments and the value of municipal bonds can be affected by uncertainties in the municipal securities market, including the occurrence of natural disasters or other events impacting markets and/or specific states and issuers. Such uncertainties could cause increased volatility in the municipal securities market and could negatively impact the Fund's net asset value and/or the distributions paid by the Fund.

Certain of the issuers in which the Fund may invest have recently experienced, or may experience, significant financial difficulties and repeated credit rating downgrades. For example, in recent years, Puerto Rico has experienced difficult financial, economic and other conditions, which may negatively affect the value of the Fund’s holdings in Puerto Rico municipal securities.

To be tax exempt, municipal bonds must meet certain regulatory requirements. If a municipal bond fails to meet such requirements, the interest received by the Fund from its investment in such bonds and distributed to shareholders may be taxable. It is possible that interest on a municipal bond may be declared taxable after the issuance of the bond, and this determination may apply retroactively to the date of the issuance of the bond, which would cause a portion of prior distributions made by the Fund to be taxable to shareholders in the year of receipt.

Risk/Return:

oef_RiskReturnAbstract

Risk [Text Block]

oef_RiskTextBlock

When-Issued Securities Risk: The Fund may agree to purchase a security on a when-issued basis, making a commitment to pay a fixed price for a security when it is issued in the future. 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/Return:

oef_RiskReturnAbstract

Risk [Text Block]

oef_RiskTextBlock

Mortgage-Related and Other Asset-Backed Securities Risk: Investments in mortgage-related securities (such as mortgage-backed securities) and other asset-backed securities generally involve a stream of payments based on the underlying obligations. These payments, which are often part interest and part return of principal, vary based on the rate at which the underlying borrowers repay their loans or other obligations. Asset-backed securities are subject to the risk that borrowers may default on the underlying obligations and that, during periods of falling interest rates, these obligations may be called or prepaid and, during periods of rising interest rates, obligations may be paid more slowly than expected. Impairment of the underlying obligations or collateral, such as by non-payment, will reduce the security's value. Enforcing rights against such collateral in events of default may be difficult or insufficient. The value of these securities may be significantly affected by changes in interest rates (or the expectations of such changes), 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.

Risk/Return:

oef_RiskReturnAbstract

Risk [Text Block]

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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.

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.

Risk/Return:

oef_RiskReturnAbstract

Average Annual Return, Percent

oef_AvgAnnlRtrPct

7.30%

Average Annual Return, Percent

oef_AvgAnnlRtrPct

2.01%

Risk/Return:

oef_RiskReturnAbstract

Average Annual Return, Percent

oef_AvgAnnlRtrPct

8.78%

Average Annual Return, Percent

oef_AvgAnnlRtrPct

3.15%

Risk/Return:

oef_RiskReturnAbstract

Maximum Deferred Sales Charge (as a percentage)

oef_MaximumDeferredSalesChargeOverOther

0.00%

^[3]

Distribution and Service (12b-1) Fees

oef_DistributionAndService12b1FeesOverAssets

0.25%

Expenses (as a percentage of Assets)

oef_ExpensesOverAssets

0.88%

Net Expenses (as a percentage of Assets)

oef_NetExpensesOverAssets

0.85%

^[5],[6]

Expenses Deferred Charges [Text Block]

oef_ExpensesDeferredChargesTextBlock

No initial sales charge applies on investments of $250,000 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, 3 Years

oef_ExpenseExampleYear03

569

Expense Example, with Redemption, 10 Years

oef_ExpenseExampleYear10

$ 1,349

Average Annual Return, Percent

oef_AvgAnnlRtrPct

(0.24%)

Performance Inception Date

oef_PerfInceptionDate

Jan. 03, 1995

Risk/Return:

oef_RiskReturnAbstract

Maximum Deferred Sales Charge (as a percentage)

oef_MaximumDeferredSalesChargeOverOther

0.00%

^[3]

Distribution and Service (12b-1) Fees

oef_DistributionAndService12b1FeesOverAssets

0.25%

Expenses (as a percentage of Assets)

oef_ExpensesOverAssets

1.30%

Net Expenses (as a percentage of Assets)

oef_NetExpensesOverAssets

1.11%

^[5],[6]

Expenses Deferred Charges [Text Block]

oef_ExpensesDeferredChargesTextBlock

No initial sales charge applies on investments of $250,000 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, 3 Years

oef_ExpenseExampleYear03

634

Expense Example, with Redemption, 10 Years

oef_ExpenseExampleYear10

$ 1,762

Average Annual Return, Percent

oef_AvgAnnlRtrPct

(0.45%)

Performance Inception Date

oef_PerfInceptionDate

Feb. 28, 2008