| N-2 - USD ($) | 3 Months Ended | 12 Months Ended | |||||||||||||
| Oct. 31, 2024 | Jul. 31, 2024 | Apr. 30, 2024 | Jan. 31, 2024 | Oct. 31, 2023 | Jul. 31, 2023 | Apr. 30, 2023 | Jan. 31, 2023 | Oct. 31, 2024 | Oct. 31, 2022 | Oct. 31, 2021 | Oct. 31, 2020 | Oct. 31, 2019 | [8] | ||
| Cover [Abstract] | |||||||||||||||
| Entity Central Index Key | 0001774342 | ||||||||||||||
| Amendment Flag | false | ||||||||||||||
| Document Type | N-CSR | ||||||||||||||
| Entity Registrant Name | Nuveen Municipal Credit Opportunities Fund | ||||||||||||||
| Fee Table [Abstract] | |||||||||||||||
| Shareholder Transaction Expenses [Table Text Block] | Shareholder Transaction Expenses NMZ NMCO NDMO Maximum Sales Charge (as a percentage of offering price) (1) 1.00% 1.00% 1.00% Dividend Reinvestment Plan Fees (2) $2.50 $2.50 $2.50 (1) The maximum sales charge for offerings made at-the-market is 1.00%. If the Common Shares are sold to or through underwriters in an offering that is not made at-the-market, the applicable Prospectus Supplement will set forth any other applicable sales load and the estimated offering expenses. Fund shareholders will pay all offering expenses involved with an offering. (2) You will be charged a $2.50 service charge and pay brokerage charges if you direct Computershare Inc. and Computershare Trust Company, N.A., as agent for the common shareholders, to sell your Common Shares held in a dividend reinvestment account. | ||||||||||||||
| Sales Load [Percent] | [1] | 1% | |||||||||||||
| Dividend Reinvestment and Cash Purchase Fees | [2] | $ 2.5 | |||||||||||||
| Other Transaction Expenses [Abstract] | |||||||||||||||
| Annual Expenses [Table Text Block] | Annual Expenses (As a Percentage of Net Assets Attributable to Common Shares) (1) NMZ NMCO NDMO Management Fees 1.05% 1.49% 1.16% Interest and Other Related Expenses (2) 2.65% 3.11% 1.68% Other Expenses (3) 0.11% 0.14% 0.14% Total Annual Expenses 3.81% 4.74% 2.99% (1) Stated as percentages of average net assets attributable to Common Shares for the fiscal year ended October 31, 2024. (2) Interest and Other Related Expenses reflect actual expenses and fees for leverage incurred by a Fund for the fiscal year ended October 31, 2024. The types of leverage used by the Fund during the fiscal year ended October 31, 2024 are described in the Fund Leverage and the Notes to Financial Statements sections of this annual report. Actual Interest and Other Related Expenses incurred in the future may be higher or lower. If short-term market interest rates rise in the future, and if the Fund continues to maintain leverage, the cost of which is tied to short-term interest rates, the Fund’s interest expenses on its short-term borrowings can be expected to rise in tandem. The Fund’s use of leverage will increase the amount of management fees paid to the Fund’s adviser and sub-advisor(s). (3) Other Expenses are based on estimated amounts for the current fiscal year. Expenses attributable to the Fund’s investments, if any, in other investment companies are currently estimated not to exceed 0.01%. | ||||||||||||||
| Management Fees [Percent] | [3] | 1.49% | |||||||||||||
| Interest Expenses on Borrowings [Percent] | [3],[4] | 3.11% | |||||||||||||
| Other Annual Expenses [Abstract] | |||||||||||||||
| Other Annual Expenses [Percent] | [3],[5] | 0.14% | |||||||||||||
| Total Annual Expenses [Percent] | [3] | 4.74% | |||||||||||||
| Expense Example [Table Text Block] | Example The following example illustrates the expenses, including the applicable transaction fees (referred to as the “Maximum Sales Charge” in the Shareholder Transaction Expenses table above), if any, that a common shareholder would pay on a $1,000 investment that is held for the time periods provided in the table. The example assumes that all dividends and other distributions are reinvested in the Fund and that the Fund’s Annual Expenses, as provided above, remain the same. The example also assumes a 5% annual return. Actual expenses may be greater or less than those assumed. Moreover, the Fund’s actual rate of return may be greater or less than the hypothetical 5% return shown in the example. Example (At-the-Market Transaction) The following example assumes a transaction fee of 1.00%, as a percentage of the offering price. 1 Year 3 Years 5 Years 10 Years NMZ $48 $125 $204 $410 NMCO $57 $151 $246 $485 NDMO $40 $102 $166 $338 The example should not be considered a representation of future expenses. Actual expenses may be greater or less than those shown above. | ||||||||||||||
| Purpose of Fee Table , Note [Text Block] | The purpose of the tables and the example below are to help you understand all fees and expenses that you, as a common shareholder, would bear directly or indirectly. The tables show the expenses of each Fund as a percentage of the average net assets applicable to Common Shares and not as a percentage of total assets or managed assets. | ||||||||||||||
| Basis of Transaction Fees, Note [Text Block] | as a percentage of offering price | ||||||||||||||
| Other Transaction Fees, Note [Text Block] | The following example illustrates the expenses, including the applicable transaction fees (referred to as the “Maximum Sales Charge” in the Shareholder Transaction Expenses table above), if any, that a common shareholder would pay on a $1,000 investment that is held for the time periods provided in the table. The example assumes that all dividends and other distributions are reinvested in the Fund and that the Fund’s Annual Expenses, as provided above, remain the same. The example also assumes a 5% annual return. Actual expenses may be greater or less than those assumed. Moreover, the Fund’s actual rate of return may be greater or less than the hypothetical 5% return shown in the example. | ||||||||||||||
| Other Expenses, Note [Text Block] | Interest and Other Related Expenses reflect actual expenses and fees for leverage incurred by a Fund for the fiscal year ended October 31, 2024. The types of leverage used by the Fund during the fiscal year ended October 31, 2024 are described in the Fund Leverage and the Notes to Financial Statements sections of this annual report. Actual Interest and Other Related Expenses incurred in the future may be higher or lower. If short-term market interest rates rise in the future, and if the Fund continues to maintain leverage, the cost of which is tied to short-term interest rates, the Fund’s interest expenses on its short-term borrowings can be expected to rise in tandem. The Fund’s use of leverage will increase the amount of management fees paid to the Fund’s adviser and sub-advisor(s). | ||||||||||||||
| Financial Highlights [Abstract] | |||||||||||||||
| Senior Securities [Table Text Block] | SENIOR SECURITIES The following table sets forth information regarding each Fund’s outstanding senior securities as of the end of each of the Fund’s last ten fiscal years, as applicable. Each Fund’s senior securities during this time period are comprised of borrowings that constitute “senior securities” as defined in the Investment Company Act of 1940, as amended (1940 Act). The information in this table as of and for the fiscal years ended 2024 through 2015 has been audited by KPMG LLP, independent registered public accounting firm. The Funds’ audited financial statements, including the report of KPMG LLP thereon, and accompanying notes thereto, are included in this Annual Report. NMCO MuniFund Preferred (MFP) Shares at the End of Period Year Ended 10/31: Aggregate Amount Outstanding (000) (1) Asset Coverage Per $100,000 Share (2) 2024 $ 415,000 $ 254,782 2023 $ 430,000 $ 228,205 2022 $ 450,000 $ 237,489 2021 $ 450,000 $ 283,171 2020 $ 450,000 $ 251,699 2019 (3) $ 0 $ 0 (1) Aggregate Amount Outstanding: Aggregate amount outstanding represents the principal amount outstanding or liquidation preference, if applicable, as of the end of the relevant fiscal year and does not include any preferred shares noticed for redemption as noted on the Statement of Assets and Liabilities, if applicable. (2) Asset Coverage Per $100,000: Asset coverage per $100,000 is calculated by subtracting the Fund’s liabilities and indebtedness not represented by senior securities from the Fund’s total assets, dividing the result by the aggregate amount of the Fund’s senior securities representing indebtedness then outstanding (if applicable), plus the aggregate of the involuntary liquidation preference of the outstanding preferred shares, if applicable, and multiplying the result by 100,000. (3) For the period September 16, 2019 (commencement of operations) through October 31, 2019. | ||||||||||||||
| Senior Securities Amount | [6] | $ 415,000 | $ 430,000 | $ 415,000 | $ 450,000 | $ 450,000 | $ 450,000 | $ 0 | [7] | ||||||
| Senior Securities Coverage per Unit | [7] | $ 254,782 | $ 228,205 | $ 254,782 | $ 237,489 | $ 283,171 | $ 251,699 | $ 0 | |||||||
| Senior Securities, Note [Text Block] | SENIOR SECURITIES The following table sets forth information regarding each Fund’s outstanding senior securities as of the end of each of the Fund’s last ten fiscal years, as applicable. Each Fund’s senior securities during this time period are comprised of borrowings that constitute “senior securities” as defined in the Investment Company Act of 1940, as amended (1940 Act). The information in this table as of and for the fiscal years ended 2024 through 2015 has been audited by KPMG LLP, independent registered public accounting firm. The Funds’ audited financial statements, including the report of KPMG LLP thereon, and accompanying notes thereto, are included in this Annual Report. | ||||||||||||||
| Senior Securities Headings, Note [Text Block] | The following table sets forth information regarding each Fund’s outstanding senior securities as of the end of each of the Fund’s last ten fiscal years, as applicable. Each Fund’s senior securities during this time period are comprised of borrowings that constitute “senior securities” as defined in the Investment Company Act of 1940, as amended (1940 Act). The information in this table as of and for the fiscal years ended 2024 through 2015 has been audited by KPMG LLP, independent registered public accounting firm. The Funds’ audited financial statements, including the report of KPMG LLP thereon, and accompanying notes thereto, are included in this Annual Report. | ||||||||||||||
| Senior Securities Highlights Audited, Note [Text Block] | The information in this table as of and for the fiscal years ended 2024 through 2015 has been audited by KPMG LLP, independent registered public accounting firm. The Funds’ audited financial statements, including the report of KPMG LLP thereon, and accompanying notes thereto, are included in this Annual Report. | ||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Investment Objectives and Practices [Text Block] | Investment Objectives The Fund’s primary investment objective is to provide a high level of current income exempt from regular U.S. federal income tax. The Fund’s secondary investment objective is to seek total return. Investment Policies Under normal circumstances, the Fund will invest at least 80% of its Assets (as defined below) in municipal securities, the income from which is exempt from regular U.S. federal income taxes. “Assets” mean the net assets of the Fund plus the amount of any borrowings for investment purposes. “Managed Assets” mean the total assets of the Fund, minus the sum of its accrued liabilities (other than Fund liabilities incurred for the express purpose of creating leverage). Total assets for this purpose shall include assets attributable to the Fund’s use of leverage (whether or not those assets are reflected in the Fund’s financial statements for purposes of generally accepted accounting principles), and derivatives will be valued at their market value. Under normal circumstances: · The Fund may invest without limit in high yielding, low- to medium-quality municipal securities (low- to medium-quality municipal securities are municipal securities rated Baa/BBB or lower) rated by at least one nationally recognized statistical rating organization (“NRSRO”) at the time of investment or are unrated but judged by the Fund’s sub-adviser to be of comparable quality. · The Fund may invest no more than 30% of its Managed Assets in municipal securities that, at the time of investment, either are rated CCC+/ Caa1 or lower, or are unrated but judged by the Fund’s sub-adviser to be of comparable quality. · The Fund may invest no more than 10% of its Managed Assets in defaulted securities or in the securities of an issuer that is in bankruptcy or insolvency proceedings. The foregoing policies apply only at the time of any new investment. Approving Changes in Investment Policies The Board of Trustees of the Fund may change the policies described above without a shareholder vote. However, with respect to the Fund’s policy of investing at least 80% of its Assets in municipal securities, the income from which is exempt from regular U.S. federal income taxes, such policy may not be changed without 60 days’ prior written notice and the approval of the holders of a majority of the outstanding common shares and preferred shares voting together as a single class, and the approval of the holders of a majority of the outstanding preferred shares, voting separately as a single class. A “majority of the outstanding” shares means (i) 67% or more of the shares present at a meeting, if the holders of more than 50% of the shares are present or represented by proxy or (ii) more than 50% of the shares, whichever is less. Portfolio Contents The Fund generally invests in municipal securities. Municipal securities include municipal bonds, notes, securities issued to finance and refinance public projects, certificates of participation, variable rate demand obligations, lease obligations, municipal notes, pre-refunded municipal bonds, private activity bonds, securities issued by tender option bond trusts (“TOB Trusts”), including inverse floating rate securities, and other forms of municipal bonds and securities, and other related instruments that create exposure to municipal bonds, notes and securities that provide for the payment of interest income that is exempt from regular United States (“U.S.”) federal income tax. Municipal securities are debt obligations generally issued by states, cities and local authorities and certain possessions and territories of the U.S. (such as Puerto Rico and Guam) to finance or refinance public purpose projects such as roads, schools, and water supply systems. The Fund may invest in municipal securities that are additionally secured by insurance, bank credit agreements or escrow accounts. The Fund may also invest in municipal securities that pay interest that is taxable under the federal alternative minimum tax applicable to noncorporate taxpayers (“AMT Bonds”). AMT Bonds may trigger adverse tax consequences for Fund shareholders who are subject to the federal alternative minimum tax. The Fund may invest in municipal securities that represent lease obligations and certificates of participation in such leases. A municipal lease is an obligation in the form of a lease or installment purchase that is issued by a state or local government to acquire equipment and facilities. Income from such obligations generally is exempt from state and local taxes in the state of issuance. A certificate of participation represents an undivided interest in an unmanaged pool of municipal leases, an installment purchase agreement or other instruments. The certificates typically are issued by a municipal agency, a trust or other entity that has received an assignment of the payments to be made by the state or political subdivision under such leases or installment purchase agreements. Such certificates provide the Fund with the right to a pro rata undivided interest in the underlying municipal securities. In addition, such participations generally provide the Fund with the right to demand payment, on not more than seven days’ notice, of all or any part of the Fund’s participation interest in the underlying municipal securities, plus accrued interest. The Fund may invest in municipal notes. Municipal securities in the form of notes generally are used to provide for short-term capital needs, in anticipation of an issuer’s receipt of other revenues or financing, and typically have maturities of up to three years. Such instruments may include tax anticipation notes, revenue anticipation notes, bond anticipation notes, tax and revenue anticipation notes and construction loan notes. Tax anticipation notes are issued to finance the working capital needs of governments. Generally, they are issued in anticipation of various tax revenues, such as income, sales, property, use and business taxes, and are payable from these specific future taxes. Revenue anticipation notes are issued in expectation of receipt of other kinds of revenue, such as federal revenues available under federal revenue sharing programs. Bond anticipation notes are issued to provide interim financing until long-term bond financing can be arranged. In most cases, the long-term bonds then provide the funds needed for repayment of the bond anticipation notes. Tax and revenue anticipation notes combine the funding sources of both tax anticipation notes and revenue anticipation notes. Construction loan notes are sold to provide construction financing. Mortgage notes insured by the Federal Housing Authority secure these notes; however, the proceeds from the insurance may be less than the economic equivalent of the payment of principal and interest on the mortgage note if there has been a default. The anticipated revenues from taxes, grants or bond financing generally secure the obligations of an issuer of municipal notes. The Fund may invest in “tobacco settlement bonds.” Tobacco settlement bonds are municipal securities that are secured or payable solely from the collateralization of the proceeds from class action or other litigation against the tobacco industry. The Fund may invest in pre-refunded municipal securities. The principal of and interest on pre-refunded municipal securities are no longer paid from the original revenue source for the securities. Instead, the source of such payments is typically an escrow fund consisting of U.S. government securities. The assets in the escrow fund are derived from the proceeds of refunding bonds issued by the same issuer as the pre-refunded municipal securities. Issuers of municipal securities use this advance refunding technique to obtain more favorable terms with respect to securities that are not yet subject to call or redemption by the issuer. For example, advance refunding enables an issuer to refinance debt at lower market interest rates, restructure debt to improve cash flow or eliminate restrictive covenants in the indenture or other governing instrument for the pre-refunded municipal securities. However, except for a change in the revenue source from which principal and interest payments are made, the pre-refunded municipal securities remain outstanding on their original terms until they mature or are redeemed by the issuer. The Fund may invest in private activity bonds. Private activity bonds are issued by or on behalf of public authorities to obtain funds to provide privately operated housing facilities, airport, mass transit or port facilities, sewage disposal, solid waste disposal or hazardous waste treatment or disposal facilities and certain local facilities for water supply, gas or electricity. Other types of private activity bonds, the proceeds of which are used for the construction, equipment, repair or improvement of privately operated industrial or commercial facilities, may constitute municipal securities, although the current federal tax laws place substantial limitations on the size of such issues. The Fund may invest in municipal securities issued by special taxing districts. Special taxing districts are organized to plan and finance infrastructure developments to induce residential, commercial and industrial growth and redevelopment. The bond financing methods such as tax increment finance, tax assessment, special services district and Mello-Roos bonds, are generally payable solely from taxes or other revenues attributable to the specific projects financed by the bonds without recourse to the credit or taxing power of related or overlapping municipalities. The Fund may invest in inverse floating rate securities issued by a TOB trust, the interest rate on which varies inversely with the Securities Industry Financial Markets Association short-term rate, which resets weekly, or a similar short-term rate, and is reduced by the expenses related to the TOB trust. Typically, inverse floating rate securities represent beneficial interests in a special purpose trust (sometimes called a TOB trust) formed by a third party sponsor for the purpose of holding municipal bonds. Inverse floating rate securities may increase or decrease in value at a greater rate than the underlying interest rate on the municipal bond held by the TOB trust, which effectively leverages the Fund’s investment. The Fund may invest in floating rate securities issued by special purpose trusts. Floating rate securities may take the form of short-term floating rate securities or the option period may be substantially longer. Generally, the interest rate earned will be based upon the market rates for municipal securities with maturities or remarketing provisions that are comparable in duration to the periodic interval of the tender option, which may vary from weekly, to monthly, to extended periods of one year or multiple years. Since the option feature has a shorter term than the final maturity or first call date of the underlying bond deposited in the trust, the Fund as the holder of the floating rate security relies upon the terms of the agreement with the financial institution furnishing the option as well as the credit strength of that institution. As further assurance of liquidity, the terms of the trust provide for a liquidation of the municipal security deposited in the trust and the application of the proceeds to pay off the floating rate security. The trusts that are organized to issue both short-term floating rate securities and inverse floaters generally include liquidation triggers to protect the investor in the floating rate security. The Fund may invest in zero coupon bonds. A zero coupon bond is a bond that typically does not pay interest for the entire life of the obligation or for an initial period after the issuance of the obligation. The Fund may buy and sell securities on a when-issued or delayed delivery basis, making payment or taking delivery at a later date, normally within 15 to 45 days of the trade date. The Fund may invest in illiquid securities (i.e., securities that are not readily marketable), including, but not limited to, restricted securities (securities the disposition of which is restricted under the federal securities laws), securities that may be resold only pursuant to Rule 144A under the Securities Act of 1933, as amended (the “1933 Act”), and repurchase agreements with maturities in excess of seven days. The Fund may enter into certain derivative instruments in pursuit of its investment objectives, including to seek to enhance return, to hedge certain risks of its investments in municipal securities or as a substitute for a position in the underlying asset. Such instruments include financial futures contracts, swap contracts (including interest rate swaps, credit default swaps and municipal market data rate locks (“MMD Rate Locks”)), options on financial futures, options on swap contracts or other derivative instruments. The Fund may purchase and sell MMD Rate Locks. An MMD Rate Lock permits the Fund to lock in a specified municipal interest rate for a portion of its portfolio to preserve a return on a particular investment or a portion of its portfolio as a duration management technique or to protect against any increase in the price of securities to be purchased at a later date. By using an MMD Rate Lock, the Fund can create a synthetic long or short position, allowing the Fund to select what the manager believes is an attractive part of the yield curve. The Fund will ordinarily use these transactions as a hedge or for duration or risk management although it is permitted to enter into them to enhance income or gain or to increase the Fund’s yield, for example, during periods of steep interest rate yield curves (i.e., wide differences between short term and long term interest rates). The Fund may also invest in securities of other open- or closed-end investment companies (including exchange-traded funds (“ETFs”)) that invest primarily in municipal securities of the types in which the Fund may invest directly, to the extent permitted by the Investment Company Act of 1940, as amended (the “1940 Act”), the rules and regulations issued thereunder and applicable exemptive orders issued by the Securities and Exchange Commission (“SEC”). The Fund may invest in distressed securities and may invest in the securities of an issuer which, at the time of investment, is in default on its obligations to pay principal or interest thereon when due or that is involved in a bankruptcy proceeding (i.e., rated below C-, at the time of investment).The Fund’s sub-adviser may determine that it is in the best interest of shareholders in pursuing a workout arrangement with issuers of defaulted securities to make loans to the defaulted issuer or another party, or purchase a debt, equity or other interest from the defaulted issuer or another party, or take other related or similar steps involving the investment of additional monies. Use of Leverage The Fund uses leverage to pursue its investment objectives. The Fund may use leverage to the extent permitted by the 1940 Act. The Fund may source leverage through a number of methods including the issuance of Preferred Shares, investments in inverse floating rate securities, entering into reverse repurchase agreements (effectively a secured borrowing), or a combination of both. In addition, the Fund may also use certain derivatives that have the economic effect of leverage by creating additional investment exposure. The amount and sources of leverage will vary depending on market conditions. Temporary Defensive Periods During temporary defensive periods (e.g., times when, in the Fund’s investment adviser’s and/or the Fund’s sub-adviser’s opinion, temporary imbalances of supply and demand or other temporary dislocations in the tax-exempt bond market adversely affect the price at which long-term or intermediate-term municipal securities are available), and in order to keep the Fund’s cash fully invested, the Fund may invest any percentage of its Managed Assets in short-term investments including high quality, short-term debt securities that may be either tax-exempt or taxable. The Fund may not achieve its investment objectives during such periods. | ||||||||||||||
| Risk Factors [Table Text Block] | PRINCIPAL RISKS OF THE FUNDS The factors that are most likely to have a material effect on a particular Fund’s portfolio as a whole are called “principal risks.” Each Fund is subject to the principal risks indicated below, whether through direct investment or derivative positions. Each Fund may be subject to additional risks other than those identified and described below because the types of investments made by a Fund can change over time. Risk NVG NZF NMZ NMCO NDMO Portfolio Level Risks Alternative Minimum Tax Risk - X X X X Below Investment Grade Risk X X X X X Call Risk X X X X X Credit Risk X X X X X Credit Spread Risk X X X X X Debt Securities Risk - - - - X Direct Lending Risk X X X X X Distressed or Defaulted Securities Risk X X X X X Deflation Risk X X X X X Derivatives Risk X X X X X Duration Risk X X X X X Economic Sector Risk X X X X X Financial Futures and Options Risk X X X X X Floating and Variable Rate Securities Risk X X X X X Hedging Risk X X X X X Illiquid Investments Risk X X X X X Income Risk X X X X X Inflation Risk X X X X X Insurance Risk X X X X X Interest Rate Risk X X X X X Inverse Floating Rate Securities Risk X X X X X Municipal Securities Risk X X X X X Municipal Securities Market Liquidity Risk X X X X X Municipal Securities Market Risk X X X X X Other Investment Companies Risk X X X X X Puerto Rico Municipal Securities Market Risk X X X X X Reinvestment Risk X X X X X Special Risks Related to Certain Municipal Obligations X X X X X Swap Transactions Risk X X X X X Tax Risk X X X X X Taxability Risk X X X X X Tobacco Settlement Bond Risk X X X X X Unrated Securities Risk X X X X X Valuation Risk X X X X X When-Issued and Delayed Delivery Transactions Risk X X X X X Zero Coupon Bonds Risk X X X X X Risk NVG NZF NMZ NMCO NDMO Fund Level and Other Risks Anti-Takeover Provisions X X X X X Counterparty Risk X X X X X Cybersecurity Risk X X X X X Economic and Political Events Risk X X X X X Fund Tax Risk X X X X X Global Economic Risk X X X X X Investment and Market Risk X X X X X Legislation and Regulatory Risk X X X X X Leverage Risk X X X X X Limited Term and Tender Offer Risks - - - X X Market Discount from Net Asset Value X X X X X Recent Market Conditions X X X X X Reverse Repurchase Agreement Risk X X X X X Portfolio Level Risks: Alternative Minimum Tax Risk. Below Investment Grade Risk. Call Risk. Credit Risk. Issuers of municipal securities in which the Fund may invest may default on their obligations to pay principal or interest when due. This non-payment would result in a reduction of income to the Fund, a reduction in the value of a municipal security experiencing non-payment and potentially a decrease in the net asset value (“NAV”) of the Fund. To the extent that the credit rating assigned to a municipal security in the Fund’s portfolio is downgraded, the market price and liquidity of such security may be adversely affected. Credit Spread Risk. Debt Securities Risk. Direct Lending Risk. As part of its lending activities, the Fund may originate loans to companies that are experiencing significant financial or business difficulties, including companies involved in bankruptcy or other reorganization and liquidation proceedings. Although the terms of such financing may result in significant financial returns to the Fund, they involve a substantial degree of risk. The level of analytical sophistication, both financial and legal, necessary for successful financing to companies experiencing significant business and financial difficulties is unusually high. Different types of assets may be used as collateral for the Fund’s loans and, accordingly, the valuation of and risks associated with such collateral will vary by loan. There is no assurance that the Fund will correctly evaluate the value of the assets collateralizing the Fund’s loans or the prospects for a successful reorganization or similar action. In any reorganization or liquidation proceeding relating to a borrower that the Fund is lending money to, the Fund may lose all or part of the amounts advanced to the borrower or may be required to accept collateral with a value less than the amount of the loan advanced by the Fund to the borrower. Furthermore, in the event of a default by a borrower, the Fund may have difficulty disposing of the assets used as collateral for a loan. To the extent the Fund seeks to engage in direct lending, the Fund will be subject to enhanced risks of litigation, regulatory actions and other proceedings. As a result, the Fund may be required to pay legal fees, settlement costs, damages, penalties or other charges, any or all of which could materially adversely affect the Fund and its holdings. Distressed or Defaulted Securities Risk. Deflation Risk. Derivatives Risk. It is possible that regulatory or other developments in the derivatives market, including changes in government regulation, could adversely impact the Fund’s ability successfully use derivative instruments. Duration Risk. Economic Sector Risk. Financial Futures and Options Transactions Risk. If the Fund engages in futures transactions or in the writing of options on futures, it will be required to maintain initial margin and maintenance margin and may be required to make daily variation margin payments in accordance with applicable rules of the exchanges and the Commodity Futures Trading Commission (“CFTC”). If the Fund purchases a financial futures contract or a call option or writes a put option in order to hedge the anticipated purchase of municipal securities, and if the Fund fails to complete the anticipated purchase transaction, the Fund may have a loss or a gain on the futures or options transaction that will not be offset by price movements in the municipal securities that were the subject of the anticipatory hedge. There can be no assurance that a liquid market will exist at a time when the Fund seeks to close out a derivatives or futures or a futures option position, and the Fund would remain obligated to meet margin requirements until the position is closed. Floating and Variable Rate Securities Risk. Hedging Risk. Illiquid Investments Risk. cash to meet its obligations. Limited liquidity can also affect the market price of investments, thereby adversely affecting the Fund’s NAV and ability to make dividend distributions. The financial markets in general have in recent years experienced periods of extreme secondary market supply and demand imbalance, resulting in a loss of liquidity during which market prices were suddenly and substantially below traditional measures of intrinsic value. During such periods, some investments could be sold only at arbitrary prices and with substantial losses. Periods of such market dislocation may occur again at any time. Income Risk. Inflation Risk. Insurance Risk. Interest Rate Risk. Inverse Floating Rate Securities Risk. The Fund may invest in inverse floating rate securities issued by special purpose trusts that have recourse to the Fund. In such instances, the Fund may be at risk of loss that exceeds its investment in the inverse floating rate securities. The Fund may be required to sell its inverse floating rate securities at less than favorable prices, or liquidate other Fund portfolio holdings in certain circumstances, including, but not limited to, the following: · If the Fund has a need for cash and the securities in a special purpose trust are not actively trading due to adverse market conditions; · If special purpose trust sponsors (as a collective group or individually) experience financial hardship and consequently seek to terminate their respective outstanding special purpose trusts; and · If the value of an underlying security declines significantly and if additional collateral has not been posted by the Fund. Municipal Securities Risk. To the extent that a fund invests a significant portion of its assets in the securities of issuers located in a given state or U.S. territory, it will be disproportionally affected by political and economic conditions and developments in that state or territory and may involve greater risk than funds that invest in a larger universe of securities. In addition, economic, political or regulatory changes in that state or territory could adversely affect municipal securities issuers in that state or territory and therefore the value of a fund’s investment portfolio. Municipal Securities Market Liquidity Risk. Municipal Securities Market Risk. Other Investment Companies Risk. With respect to ETF’s, an ETF that is based on a specific index may not be able to replicate and maintain exactly the composition and relative weighting of securities in the index. The value of an ETF based on a specific index is subject to change as the values of its respective component assets fluctuate according to market volatility. ETFs typically rely on a limited pool of authorized participants to create and redeem shares, and an active trading market for ETF shares may not develop or be maintained. The market value of shares of ETFs and closed-end funds may differ from their NAV. Puerto Rico Municipal Securities Market Risk. Puerto Rico currently is experiencing significant fiscal and economic challenges, including substantial debt service obligations, high levels of unemployment, underfunded public retirement systems, and persistent government budget deficits. These challenges may negatively affect the value of the Fund’s investments in Puerto Rican municipal securities. Several major ratings agencies have downgraded the general obligation debt of Puerto Rico to below investment grade and continue to maintain a negative outlook for this debt, which increases the likelihood that the rating will be lowered further. In both August 2015 and January 2016, Puerto Rico defaulted on its debt by failing to make full payment due on its outstanding bonds, and there can be no assurance that Puerto Rico will be able to satisfy its future debt obligations. Further downgrades or defaults may place additional strain on the Puerto Rico economy and may negatively affect the value, liquidity, and volatility of the Fund’s investments in Puerto Rican municipal securities. Additionally, numerous issuers have entered Title III of the Puerto Rico Oversite, Management and Economic Stability Act (“PROMESA”), which is similar to bankruptcy protection, through which the Commonwealth of Puerto Rico can restructure its debt. However, Puerto Rico’s case is the first ever heard under PROMESA and there is no existing case precedent to guide the proceedings. Accordingly, Puerto Rico’s debt restructuring process could take significantly longer than traditional municipal bankruptcy proceedings. Further, it is not clear whether a debt restructuring process will ultimately be approved or, if so, the extent to which it will apply to Puerto Rico municipal securities sold by an issuer other than the territory. A debt restructuring could reduce the principal amount due, the interest rate, the maturity, and other terms of Puerto Rico municipal securities, which could adversely affect the value of Puerto Rican municipal securities. Legislation, including PROMESA that would allow Puerto Rico to restructure its municipal debt obligations, thus increasing the risk that Puerto Rico may never pay off municipal indebtedness, or may pay only a small fraction of the amount owed, could also impact the value of the Fund’s investments in Puerto Rican municipal securities. These challenges and uncertainties have been exacerbated by Hurricanes Irma and Maria and the resulting natural disaster in Puerto Rico. In September 2017, Hurricanes Irma and Maria struck Puerto Rico, causing major damage across the Commonwealth, including damage to its water, power, and telecommunications infrastructure. The length of time needed to rebuild Puerto Rico’s infrastructure is unclear, but could amount to years, during which the Commonwealth is likely to be in an uncertain economic state. The full extent of the natural disaster’s impact on Puerto Rico’s economy and foreign investment in Puerto Rico is difficult to estimate. More recently, in late December 2019 and January 2020, a series of earthquakes hit Puerto Rico, including a magnitude 6.4 earthquake, the most powerful earthquake to hit the island in more than a century, causing an estimated $200 million in damage. In addition, in early 2020, as the population of Puerto Rico worked to recover from these natural disasters, the island was significantly impacted by Covid, resulting in the Commonwealth’s authorization of a $787 million relief package to fight the pandemic and its economic impacts. Any reduction in the Commonwealth’s revenues as a result of the pandemic could have a negative ability on the Commonwealth to meet its debt service obligations, including with respect to debt held by the Fund. Puerto Rico’s political and economic conditions could have a negative impact on the liquidity or value of Puerto Rican municipal securities, and consequently may affect the Fund’s investments and its performance if the Fund invests a significant portion of its assets in Puerto Rican municipal securities. Reinvestment Risk. Special Risks Related to Certain Municipal Obligations. Certificates of participation involve the same risks as the underlying municipal leases. In addition, the Fund may be dependent upon the municipal authority issuing the certificates of participation to exercise remedies with respect to the underlying securities. Certificates of participation also entail a risk of default or bankruptcy, both of the issuer of the municipal lease and also the municipal agency issuing the certificate of participation. Swap Transactions Risk. Tax Risk. Taxability Risk. Tobacco Settlement Bond Risk. Unrated Securities Risk. Valuation Risk. pricing services may incorporate different assumptions and inputs into their valuation methodologies, potentially resulting in different values for the same securities. As a result, if the Fund were to change pricing services, or if the Fund’s pricing service were to change its valuation methodology, there could be a material impact, either positive or negative, on the Fund’s NAV. When-Issued and Delayed-Delivery Transactions Risk. Zero Coupon Bonds Risk. Fund Level and Other Risks: Anti-Takeover Provisions. Counterparty Risk . Cybersecurity Risk. Economic and Political Events Risk. Fund Tax Risk. Global Economic Risk. as the United States, United Kingdom, European Union and Canada. The current sanctions and potential further sanctions may negatively impact certain sectors of Russia’s economy, but also may negatively impact the value of the Fund’s investments that do not have direct exposure to Russia. These events could reduce consumer demand or economic output, result in market closure, travel restrictions or quarantines, and generally have a significant impact on the global economy. These events could also impair the information technology and other operational systems upon which the Fund’s service providers, including the Fund’s sub-adviser, rely, and could otherwise disrupt the ability of employees of the Fund’s service providers to perform essential tasks on behalf of the Fund. The Fund does not know and cannot predict how long the securities markets may be affected by these events, and the future impact of these and similar events on the global economy and securities markets is uncertain. The Fund may be adversely affected by abrogation of international agreements and national laws which have created the market instruments in which the Fund may invest, failure of the designated national and international authorities to enforce compliance with the same laws and agreements, failure of local, national and international organizations to carry out the duties prescribed to them under the relevant agreements, revisions of these laws and agreements which dilute their effectiveness or conflicting interpretation of provisions of the same laws and agreements. Governmental and quasi-governmental authorities and regulators throughout the world have in the past responded to major economic disruptions with a variety of significant fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. An unexpected or quick reversal of these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which could adversely affect the Fund’s investments. Investment and Market Risk. Legislation and Regulatory Risk. Leverage Risk. Certain types of leverage may result in the Fund being subject to certain covenants, asset coverage or other portfolio composition limits by its lenders, debt or preferred securities purchasers, rating agencies that may rate the debt or preferred securities, or reverse repurchase counterparties. Such limitations may be more stringent than those imposed by the 1940 Act and may impact whether the Fund is able to maintain its desired amount of leverage. In addition, whenever the Fund incurs borrowings and/or preferred shares are outstanding, Common Shareholders will not be entitled to receive any cash distributions from the Fund unless all interest on such borrowings has been paid and all accumulated dividends on preferred shares have been paid, unless asset coverage (as defined in the 1940 Act) with respect to any borrowings would be at least 300% after giving effect to the distributions and asset coverage (as defined in the 1940 Act) with respect to preferred shares would be at least 200% after giving effect to the distributions. The Fund will pay (and common shareholders will bear) any costs and expenses relating to the Fund’s use of leverage, which will result in a reduction in the Fund’s NAV. The investment adviser may, based on its assessment of market conditions, composition of the Fund’s holdings, increase or decrease the amount of leverage. Such changes may impact the Fund’s distributions and the price of the common shares in the secondary market. There is no assurance that the Fund’s use of leverage will be successful. The Fund may seek to refinance its leverage over time, in the ordinary course, as current forms of leverage mature or it is otherwise desirable to refinance; however, the form that such leverage will take cannot be predicted at this time. If the Fund is unable to replace existing leverage on comparable terms, its costs of leverage will increase. Accordingly, there is no assurance that the use of leverage may result in a higher yield or return to common shareholders. The amount of fees paid to the investment adviser and the sub-advisor for investment advisory services will be higher if the Fund uses leverage because the fees will be calculated based on the Fund’s Managed Assets - this may create an incentive for the investment adviser and the sub-advisor to leverage the Fund or increase the Fund’s leverage. Limited Term and Tender Offer Risks. The Fund may be required to dispose of portfolio investments in connection with any reduction in its outstanding leverage necessary in order to maintain its desired leverage ratios following an Eligible Tender Offer. It is likely that during the pendency of an Eligible Tender Offer, and possibly for a time thereafter, the Fund will hold a greater than normal percentage of its total assets in money market mutual funds, cash, cash equivalents, securities issued or guaranteed by the U.S. government or its instrumentalities or agencies, high quality, short-term money market instruments, short-term debt securities, certificates of deposit, bankers’ acceptances and other bank obligations, commercial paper or other liquid debt securities, which may adversely affect the Fund’s investment performance. If the tax basis for the portfolio investments sold is less than the sale proceeds, the Fund will recognize capital gains, which it will be required to distribute to Common Shareholders. In addition, the Fund’s purchase of tendered Common Shares pursuant to an Eligible Tender Offer will have tax consequences for tendering Common Shareholders and may have tax consequences for non-tendering Common Shareholders. All Common Shareholders remaining after an Eligible Tender Offer will be subject to proportionately higher expenses due to the reduction in the Fund’s total assets resulting from payment for the tendered Common Shares. Such reduction in the Fund’s total assets also may result in less investment flexibility, reduced diversification and greater volatility for the Fund, and may have an adverse effect on the Fund’s investment performance. If the Fund conducts an Eligible Tender Offer, there can be no assurance that the number of tendered Common Shares would not result in the Fund’s net assets totaling less than the Termination Threshold, in which case the Eligible Tender Offer will be terminated, no Common Shares will be repurchased pursuant to the Eligible Tender Offer and the Fund will terminate on the Termination Date. The investment adviser may have a conflict of interest in recommending to the Board of Trustees that the Fund have a continued existence without limitation of time. The Fund is not required to conduct additional tender offers following an Eligible Tender Offer and conversion to a continued existence without limitation of time. Therefore, remaining Common Shareholders may not have another opportunity to participate in a tender offer. A Fund portfolio holding default may significantly reduce net investment income and, therefore, Common Share dividends; and may prevent or inhibit the Fund from fully being able to liquidate its portfolio at or prior to the Termination Date. Market Discount from Net Asset Value. Recent Market Conditions. Ukraine has experienced ongoing military conflict, most recently in February 2022 when Russia invaded Ukraine; this conflict may expand and military attacks could occur elsewhere in Europe. Europe has also been struggling with mass migration from the Middle East and Africa. The ultimate effects of these events and other socio-political or geographical issues are not known but could profoundly affect global economies and markets. Additionally, in October 2023 armed conflict broke out between Israel and the militant group Hamas after Hamas infiltrated Israel’s southern border from the Gaza Strip. Israel has since declared war against Hamas and it’s possible that this conflict could escalate into a greater regional conflict. The ultimate effects of these events and other socio-political or geographical issues are not known but could profoundly affect global economies and markets. The ongoing trade war between China and the United States, including the imposition of tariffs by each country on the other country’s products, has created a tense political environment. These actions may trigger a significant reduction in international trade, the oversupply of certain manufactured goods, substantial price reductions of goods and possible failure of individual companies and/or large segments of China’s export industry, which could have a negative impact on the Fund’s performance. U.S. companies that source material and goods from China and those that make large amounts of sales in China would be particularly vulnerable to an escalation of trade tensions. Uncertainty regarding the outcome of the trade tensions and the potential for a trade war could cause the U.S. dollar to decline against safe haven currencies, such as the Japanese yen and the euro. Events such as these and their consequences are difficult to predict and it is unclear whether further tariffs may be imposed or other escalating actions may be taken in the future. The U.S. Federal Reserve (the “Fed”) has in the past sharply raised interest rates, and while the Fed has recently lowered the federal funds rates, it has signaled an intention to maintain relatively higher interest rates until current inflation levels re-align with the Fed’s long-term inflation target. Changing interest rate environments impact the various sectors of the economy in different ways. For example, in March 2023, the Federal Deposit Insurance Corporation (“FDIC”) was appointed receiver for each of Silicon Valley Bank and Signature Bank, the second- and third-largest bank failures in U.S. history, which failures may be attributable, in part, to rising interest rates. Bank failures may have a destabilizing impact on the broader banking industry or markets generally. The impact of these developments in the near- and long-term is unknown and could have additional adverse effects on economies, financial markets and asset valuations around the world. Reverse Repurchase Agreement Risk. 231 agreed upon, files for bankruptcy or becomes insolvent. The Fund may be restricted from taking normal portfolio actions during such time, could be subject to loss to the extent that the proceeds of the agreement are less than the value of securities subject to the agreement and may experience adverse tax consequences. | ||||||||||||||
| Effects of Leverage [Text Block] | EFFECTS OF LEVERAGE The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effects of leverage through the use of senior securities, as that term is defined under Section 18 of the 1940 Act, as well as certain other forms of leverage, such as reverse repurchase agreements and investments in inverse floating rate securities, on common share total return, assuming investment portfolio total returns (consisting of income and changes in the value of investments held in a Fund’s portfolio) of -10%, -5%, 0%, 5% and 10%. The table below reflects each Fund’s (i) continued use of leverage as of October 31, 2024 as a percentage of Managed Assets (including assets attributable to such leverage), (ii) the estimated annual effective interest expense rate payable by the Funds on such instruments (based on actual leverage costs incurred during the fiscal year ended October 31, 2024) as set forth in the table, and (iii) the annual return that the Fund’s portfolio must experience (net of expenses) in order to cover such costs of leverage based on such estimated annual effective interest expense rate. The information below does not reflect any Fund’s use of certain derivative instruments. The numbers are merely estimates, used for illustration. The costs of leverage may vary frequently and may be significantly higher or lower than the estimated rate. The assumed investment portfolio returns in the table below are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Funds. Your actual returns may be greater or less than those appearing below. Nuveen AMT-Free Municipal Credit Income Fund (NVG) Nuveen Municipal Credit Income Fund (NZF) Nuveen Municipal High Income Opportunity Fund (NMZ) Nuveen Municipal Credit Opportunities Fund (NMCO) Nuveen Dynamic Municipal Opportunities Fund (NDMO) Estimated Leverage as a Percentage of Managed Assets (Including Assets Attributable to Leverage) 40.37% 39.49% 39.68% 41.25% 28.87% Estimated Annual Effective Leverage Expense Rate Payable by Fund on Leverage 4.31% 4.38% 4.17% 4.47% 4.36% Annual Return Fund Portfolio Must Experience (net of expenses) to Cover Estimated Annual Effective Interest Expense Rate on Leverage 1.74% 1.73% 1.66% 1.84% 1.26% Common Share Total Return for (10.00)% Assumed Portfolio Total Return (19.69)% (19.39)% (19.32)% (20.16)% (15.83)% Common Share Total Return for (5.00)% Assumed Portfolio Total Return (11.30)% (11.13)% (11.03)% (11.65)% (8.80)% Common Share Total Return for 0.00% Assumed Portfolio Total Return (2.92)% (2.86)% (2.74)% (3.14)% (1.77)% Common Share Total Return for 5.00% Assumed Portfolio Total Return 5.47% 5.40% 5.55% 5.37% 5.26% Common Share Total Return for 10.00% Assumed Portfolio Total Return 13.85% 13.67% 13.83% 13.89% 12.29% Common Share total return is composed of two elements — the distributions paid by the Fund to holders of common shares (the amount of which is largely determined by the net investment income of the Fund after paying dividend payments on any preferred shares issued by the Fund and expenses on any forms of leverage outstanding) and gains or losses on the value of the securities and other instruments the Fund owns. As required by SEC rules, the table assumes that the Funds are more likely to suffer capital losses than to enjoy capital appreciation. For example, to assume a total return of 0%, the Fund must assume that the income it receives on its investments is entirely offset by losses in the value of those investments. This table reflects hypothetical performance of the Fund’s portfolio and not the actual performance of the Fund’s common shares, the value of which is determined by market forces and other factors. Should the Fund elect to add additional leverage to its portfolio, any benefits of such additional leverage cannot be fully achieved until the proceeds resulting from the use of such leverage have been received by the Fund and invested in accordance with the Fund’s investment objectives and policies. As noted above, the Fund’s willingness to use additional leverage, and the extent to which leverage is used at any time, will depend on many factors. | ||||||||||||||
| Annual Interest Rate, Initial [Percent] | 41.25% | ||||||||||||||
| Annual Interest Rate, Current [Percent] | 4.47% | ||||||||||||||
| Annual Coverage Return Rate [Percent] | 1.84% | ||||||||||||||
| Effects of Leverage [Table Text Block] | Nuveen AMT-Free Municipal Credit Income Fund (NVG) Nuveen Municipal Credit Income Fund (NZF) Nuveen Municipal High Income Opportunity Fund (NMZ) Nuveen Municipal Credit Opportunities Fund (NMCO) Nuveen Dynamic Municipal Opportunities Fund (NDMO) Estimated Leverage as a Percentage of Managed Assets (Including Assets Attributable to Leverage) 40.37% 39.49% 39.68% 41.25% 28.87% Estimated Annual Effective Leverage Expense Rate Payable by Fund on Leverage 4.31% 4.38% 4.17% 4.47% 4.36% Annual Return Fund Portfolio Must Experience (net of expenses) to Cover Estimated Annual Effective Interest Expense Rate on Leverage 1.74% 1.73% 1.66% 1.84% 1.26% Common Share Total Return for (10.00)% Assumed Portfolio Total Return (19.69)% (19.39)% (19.32)% (20.16)% (15.83)% Common Share Total Return for (5.00)% Assumed Portfolio Total Return (11.30)% (11.13)% (11.03)% (11.65)% (8.80)% Common Share Total Return for 0.00% Assumed Portfolio Total Return (2.92)% (2.86)% (2.74)% (3.14)% (1.77)% Common Share Total Return for 5.00% Assumed Portfolio Total Return 5.47% 5.40% 5.55% 5.37% 5.26% Common Share Total Return for 10.00% Assumed Portfolio Total Return 13.85% 13.67% 13.83% 13.89% 12.29% | ||||||||||||||
| Return at Minus Ten [Percent] | (20.16%) | ||||||||||||||
| Return at Minus Five [Percent] | (11.65%) | ||||||||||||||
| Return at Zero [Percent] | (3.14%) | ||||||||||||||
| Return at Plus Five [Percent] | 5.37% | ||||||||||||||
| Return at Plus Ten [Percent] | 13.89% | ||||||||||||||
| Effects of Leverage, Purpose [Text Block] | The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effects of leverage through the use of senior securities, as that term is defined under Section 18 of the 1940 Act, as well as certain other forms of leverage, such as reverse repurchase agreements and investments in inverse floating rate securities, on common share total return, assuming investment portfolio total returns (consisting of income and changes in the value of investments held in a Fund’s portfolio) of -10%, -5%, 0%, 5% and 10%. The table below reflects each Fund’s (i) continued use of leverage as of October 31, 2024 as a percentage of Managed Assets (including assets attributable to such leverage), (ii) the estimated annual effective interest expense rate payable by the Funds on such instruments (based on actual leverage costs incurred during the fiscal year ended October 31, 2024) as set forth in the table, and (iii) the annual return that the Fund’s portfolio must experience (net of expenses) in order to cover such costs of leverage based on such estimated annual effective interest expense rate. The information below does not reflect any Fund’s use of certain derivative instruments. | ||||||||||||||
| Share Price [Table Text Block] | TRADING AND NET ASSET VALUE INFORMATION The following table shows for the periods indicated: (i) the high and low sales prices for the Common Shares reported as of the end of the day on the NYSE, (ii) the high and low net asset value (NAV) of the Common Shares, and (iii) the high and low of the premium/(discount) to NAV (expressed as a percentage) of shares of the Common Shares. NMCO Market Price NAV Premium/(Discount) to NAV Fiscal Quarter End High Low High Low High Low October 2024 $12.14 $10.96 $12.29 $11.70 (1.22)% (6.32)% July 2024 $11.20 $10.25 $12.18 $11.51 (8.05)% (10.95)% April 2024 $10.69 $10.08 $11.82 $11.54 (9.56)% (12.65)% January 2024 $10.27 $8.87 $11.39 $10.07 (9.83)% (11.92)% October 2023 $11.54 $8.62 $11.61 $10.07 (0.60)% (14.40)% July 2023 $11.43 $10.74 $11.72 $11.66 (2.47)% (7.89)% April 2023 $12.41 $10.83 $12.37 $11.80 0.32% (8.22)% January 2023 $12.49 $10.47 $12.40 $11.19 0.73% (6.43)% The following table shows, as of October 31, 2024 each Fund’s: (i) NAV per Common Share, (ii) market price, (iii) percentage of premium/(discount) to NAV per Common Share and, (iv) net assets attributable to Common Shares. October 31, 2024 NMZ NMCO NDMO NAV per Common Share $11.19 $11.72 $11.09 Market Price $11.15 $11.10 $10.72 Percentage of Premium/(Discount) to NAV per Common Share (0.36)% (5.29)% (3.34)% Net Assets Attributable to Common Shares $ 1,248,724,818 $ 642,344,969 $ 660,631,168 Shares of closed-end investment companies, including those of the Funds, may frequently trade at prices lower than NAV, the Funds’ Board of Trustees (Board) has currently determined that, at least annually, it will consider action that might be taken to reduce or eliminate any material discount from NAV in respect of Common Shares, which may include the repurchase of such shares in the open market or in private transactions, the making of a tender offer for such shares at NAV, or the conversion of the Fund to an open-end investment company. The Funds cannot assure you that their Board will decide to take any of these actions, or that share repurchases or tender offers will actually reduce market discount. | ||||||||||||||
| Lowest Price or Bid | 10.96 | $ 10.25 | $ 10.08 | $ 8.87 | 8.62 | $ 10.74 | $ 10.83 | $ 10.47 | |||||||
| Highest Price or Bid | 12.14 | 11.2 | 10.69 | 10.27 | 11.54 | 11.43 | 12.41 | 12.49 | |||||||
| Lowest Price or Bid, NAV | 11.7 | 11.51 | 11.54 | 10.07 | 10.07 | 11.66 | 11.8 | 11.19 | |||||||
| Highest Price or Bid, NAV | $ 12.29 | $ 12.18 | $ 11.82 | $ 11.39 | $ 11.61 | $ 11.72 | $ 12.37 | $ 12.4 | |||||||
| Highest Price or Bid, Premium (Discount) to NAV [Percent] | (1.22%) | (8.05%) | (9.56%) | (9.83%) | (0.60%) | (2.47%) | 0.32% | 0.73% | |||||||
| Lowest Price or Bid, Premium (Discount) to NAV [Percent] | (6.32%) | (10.95%) | (12.65%) | (11.92%) | (14.40%) | (7.89%) | (8.22%) | (6.43%) | |||||||
| Share Price | $ 11.1 | $ 11.1 | |||||||||||||
| NAV Per Share | $ 1.72 | $ 1.72 | |||||||||||||
| Latest Premium (Discount) to NAV [Percent] | (5.29%) | ||||||||||||||
| Alternative Minimum Tax Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Alternative Minimum Tax Risk. | ||||||||||||||
| Below Investment Grade Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Below Investment Grade Risk. | ||||||||||||||
| Call Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Call Risk. | ||||||||||||||
| Credits Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Credit Risk. Issuers of municipal securities in which the Fund may invest may default on their obligations to pay principal or interest when due. This non-payment would result in a reduction of income to the Fund, a reduction in the value of a municipal security experiencing non-payment and potentially a decrease in the net asset value (“NAV”) of the Fund. To the extent that the credit rating assigned to a municipal security in the Fund’s portfolio is downgraded, the market price and liquidity of such security may be adversely affected. | ||||||||||||||
| Credit Spread Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Credit Spread Risk. | ||||||||||||||
| Distressed or Defaulted Securities Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Distressed or Defaulted Securities Risk. | ||||||||||||||
| Deflation Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Deflation Risk. | ||||||||||||||
| Derivatives Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Derivatives Risk. It is possible that regulatory or other developments in the derivatives market, including changes in government regulation, could adversely impact the Fund’s ability successfully use derivative instruments. | ||||||||||||||
| Duration Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Duration Risk. | ||||||||||||||
| Economic Sector Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Economic Sector Risk. | ||||||||||||||
| Financial Futures and Options Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Financial Futures and Options Transactions Risk. If the Fund engages in futures transactions or in the writing of options on futures, it will be required to maintain initial margin and maintenance margin and may be required to make daily variation margin payments in accordance with applicable rules of the exchanges and the Commodity Futures Trading Commission (“CFTC”). If the Fund purchases a financial futures contract or a call option or writes a put option in order to hedge the anticipated purchase of municipal securities, and if the Fund fails to complete the anticipated purchase transaction, the Fund may have a loss or a gain on the futures or options transaction that will not be offset by price movements in the municipal securities that were the subject of the anticipatory hedge. There can be no assurance that a liquid market will exist at a time when the Fund seeks to close out a derivatives or futures or a futures option position, and the Fund would remain obligated to meet margin requirements until the position is closed. | ||||||||||||||
| Hedging Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Hedging Risk. | ||||||||||||||
| Illiquid Investments Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Illiquid Investments Risk. cash to meet its obligations. Limited liquidity can also affect the market price of investments, thereby adversely affecting the Fund’s NAV and ability to make dividend distributions. The financial markets in general have in recent years experienced periods of extreme secondary market supply and demand imbalance, resulting in a loss of liquidity during which market prices were suddenly and substantially below traditional measures of intrinsic value. During such periods, some investments could be sold only at arbitrary prices and with substantial losses. Periods of such market dislocation may occur again at any time. | ||||||||||||||
| Income Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Income Risk. | ||||||||||||||
| Inflation Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Inflation Risk. | ||||||||||||||
| Insurance Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Insurance Risk. | ||||||||||||||
| Inverse Floating Rate Securities Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Inverse Floating Rate Securities Risk. The Fund may invest in inverse floating rate securities issued by special purpose trusts that have recourse to the Fund. In such instances, the Fund may be at risk of loss that exceeds its investment in the inverse floating rate securities. The Fund may be required to sell its inverse floating rate securities at less than favorable prices, or liquidate other Fund portfolio holdings in certain circumstances, including, but not limited to, the following: · If the Fund has a need for cash and the securities in a special purpose trust are not actively trading due to adverse market conditions; · If special purpose trust sponsors (as a collective group or individually) experience financial hardship and consequently seek to terminate their respective outstanding special purpose trusts; and · If the value of an underlying security declines significantly and if additional collateral has not been posted by the Fund. | ||||||||||||||
| Municipal Securities Market Liquidity Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Municipal Securities Market Liquidity Risk. | ||||||||||||||
| Municipal Securities Market Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Municipal Securities Market Risk. | ||||||||||||||
| Other Investment Companies Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Other Investment Companies Risk. With respect to ETF’s, an ETF that is based on a specific index may not be able to replicate and maintain exactly the composition and relative weighting of securities in the index. The value of an ETF based on a specific index is subject to change as the values of its respective component assets fluctuate according to market volatility. ETFs typically rely on a limited pool of authorized participants to create and redeem shares, and an active trading market for ETF shares may not develop or be maintained. The market value of shares of ETFs and closed-end funds may differ from their NAV. | ||||||||||||||
| Puerto Rico Municipal Securities Market Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Puerto Rico Municipal Securities Market Risk. Puerto Rico currently is experiencing significant fiscal and economic challenges, including substantial debt service obligations, high levels of unemployment, underfunded public retirement systems, and persistent government budget deficits. These challenges may negatively affect the value of the Fund’s investments in Puerto Rican municipal securities. Several major ratings agencies have downgraded the general obligation debt of Puerto Rico to below investment grade and continue to maintain a negative outlook for this debt, which increases the likelihood that the rating will be lowered further. In both August 2015 and January 2016, Puerto Rico defaulted on its debt by failing to make full payment due on its outstanding bonds, and there can be no assurance that Puerto Rico will be able to satisfy its future debt obligations. Further downgrades or defaults may place additional strain on the Puerto Rico economy and may negatively affect the value, liquidity, and volatility of the Fund’s investments in Puerto Rican municipal securities. Additionally, numerous issuers have entered Title III of the Puerto Rico Oversite, Management and Economic Stability Act (“PROMESA”), which is similar to bankruptcy protection, through which the Commonwealth of Puerto Rico can restructure its debt. However, Puerto Rico’s case is the first ever heard under PROMESA and there is no existing case precedent to guide the proceedings. Accordingly, Puerto Rico’s debt restructuring process could take significantly longer than traditional municipal bankruptcy proceedings. Further, it is not clear whether a debt restructuring process will ultimately be approved or, if so, the extent to which it will apply to Puerto Rico municipal securities sold by an issuer other than the territory. A debt restructuring could reduce the principal amount due, the interest rate, the maturity, and other terms of Puerto Rico municipal securities, which could adversely affect the value of Puerto Rican municipal securities. Legislation, including PROMESA that would allow Puerto Rico to restructure its municipal debt obligations, thus increasing the risk that Puerto Rico may never pay off municipal indebtedness, or may pay only a small fraction of the amount owed, could also impact the value of the Fund’s investments in Puerto Rican municipal securities. These challenges and uncertainties have been exacerbated by Hurricanes Irma and Maria and the resulting natural disaster in Puerto Rico. In September 2017, Hurricanes Irma and Maria struck Puerto Rico, causing major damage across the Commonwealth, including damage to its water, power, and telecommunications infrastructure. The length of time needed to rebuild Puerto Rico’s infrastructure is unclear, but could amount to years, during which the Commonwealth is likely to be in an uncertain economic state. The full extent of the natural disaster’s impact on Puerto Rico’s economy and foreign investment in Puerto Rico is difficult to estimate. More recently, in late December 2019 and January 2020, a series of earthquakes hit Puerto Rico, including a magnitude 6.4 earthquake, the most powerful earthquake to hit the island in more than a century, causing an estimated $200 million in damage. In addition, in early 2020, as the population of Puerto Rico worked to recover from these natural disasters, the island was significantly impacted by Covid, resulting in the Commonwealth’s authorization of a $787 million relief package to fight the pandemic and its economic impacts. Any reduction in the Commonwealth’s revenues as a result of the pandemic could have a negative ability on the Commonwealth to meet its debt service obligations, including with respect to debt held by the Fund. Puerto Rico’s political and economic conditions could have a negative impact on the liquidity or value of Puerto Rican municipal securities, and consequently may affect the Fund’s investments and its performance if the Fund invests a significant portion of its assets in Puerto Rican municipal securities. | ||||||||||||||
| Reinvestment Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Reinvestment Risk. | ||||||||||||||
| Special Risks Related to Certain Municipal Obligations [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Special Risks Related to Certain Municipal Obligations. Certificates of participation involve the same risks as the underlying municipal leases. In addition, the Fund may be dependent upon the municipal authority issuing the certificates of participation to exercise remedies with respect to the underlying securities. Certificates of participation also entail a risk of default or bankruptcy, both of the issuer of the municipal lease and also the municipal agency issuing the certificate of participation. | ||||||||||||||
| Swap Transactions Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Swap Transactions Risk. | ||||||||||||||
| Tax Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Tax Risk. | ||||||||||||||
| Taxability Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Taxability Risk. | ||||||||||||||
| Tobacco Settlement Bond Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Tobacco Settlement Bond Risk. | ||||||||||||||
| Unrated Securities Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Unrated Securities Risk. | ||||||||||||||
| Valuation Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Valuation Risk. pricing services may incorporate different assumptions and inputs into their valuation methodologies, potentially resulting in different values for the same securities. As a result, if the Fund were to change pricing services, or if the Fund’s pricing service were to change its valuation methodology, there could be a material impact, either positive or negative, on the Fund’s NAV. | ||||||||||||||
| Zero Coupon Bonds Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Zero Coupon Bonds Risk. | ||||||||||||||
| AntiTakeover Provisions [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Anti-Takeover Provisions. | ||||||||||||||
| Counterparty Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Counterparty Risk . | ||||||||||||||
| Cybersecurity Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Cybersecurity Risk. | ||||||||||||||
| Economic and Political Events Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Economic and Political Events Risk. | ||||||||||||||
| Fund Tax Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Fund Tax Risk. | ||||||||||||||
| Global Economic Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Global Economic Risk. as the United States, United Kingdom, European Union and Canada. The current sanctions and potential further sanctions may negatively impact certain sectors of Russia’s economy, but also may negatively impact the value of the Fund’s investments that do not have direct exposure to Russia. These events could reduce consumer demand or economic output, result in market closure, travel restrictions or quarantines, and generally have a significant impact on the global economy. These events could also impair the information technology and other operational systems upon which the Fund’s service providers, including the Fund’s sub-adviser, rely, and could otherwise disrupt the ability of employees of the Fund’s service providers to perform essential tasks on behalf of the Fund. The Fund does not know and cannot predict how long the securities markets may be affected by these events, and the future impact of these and similar events on the global economy and securities markets is uncertain. The Fund may be adversely affected by abrogation of international agreements and national laws which have created the market instruments in which the Fund may invest, failure of the designated national and international authorities to enforce compliance with the same laws and agreements, failure of local, national and international organizations to carry out the duties prescribed to them under the relevant agreements, revisions of these laws and agreements which dilute their effectiveness or conflicting interpretation of provisions of the same laws and agreements. Governmental and quasi-governmental authorities and regulators throughout the world have in the past responded to major economic disruptions with a variety of significant fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. An unexpected or quick reversal of these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which could adversely affect the Fund’s investments. | ||||||||||||||
| Investment and Market Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Investment and Market Risk. | ||||||||||||||
| Legislation and Regulatory Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Legislation and Regulatory Risk. | ||||||||||||||
| Leverage Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Leverage Risk. Certain types of leverage may result in the Fund being subject to certain covenants, asset coverage or other portfolio composition limits by its lenders, debt or preferred securities purchasers, rating agencies that may rate the debt or preferred securities, or reverse repurchase counterparties. Such limitations may be more stringent than those imposed by the 1940 Act and may impact whether the Fund is able to maintain its desired amount of leverage. In addition, whenever the Fund incurs borrowings and/or preferred shares are outstanding, Common Shareholders will not be entitled to receive any cash distributions from the Fund unless all interest on such borrowings has been paid and all accumulated dividends on preferred shares have been paid, unless asset coverage (as defined in the 1940 Act) with respect to any borrowings would be at least 300% after giving effect to the distributions and asset coverage (as defined in the 1940 Act) with respect to preferred shares would be at least 200% after giving effect to the distributions. The Fund will pay (and common shareholders will bear) any costs and expenses relating to the Fund’s use of leverage, which will result in a reduction in the Fund’s NAV. The investment adviser may, based on its assessment of market conditions, composition of the Fund’s holdings, increase or decrease the amount of leverage. Such changes may impact the Fund’s distributions and the price of the common shares in the secondary market. There is no assurance that the Fund’s use of leverage will be successful. The Fund may seek to refinance its leverage over time, in the ordinary course, as current forms of leverage mature or it is otherwise desirable to refinance; however, the form that such leverage will take cannot be predicted at this time. If the Fund is unable to replace existing leverage on comparable terms, its costs of leverage will increase. Accordingly, there is no assurance that the use of leverage may result in a higher yield or return to common shareholders. The amount of fees paid to the investment adviser and the sub-advisor for investment advisory services will be higher if the Fund uses leverage because the fees will be calculated based on the Fund’s Managed Assets - this may create an incentive for the investment adviser and the sub-advisor to leverage the Fund or increase the Fund’s leverage. | ||||||||||||||
| Market Discount from Net Asset Value [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Market Discount from Net Asset Value. | ||||||||||||||
| Recent Market Conditions [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Recent Market Conditions. Ukraine has experienced ongoing military conflict, most recently in February 2022 when Russia invaded Ukraine; this conflict may expand and military attacks could occur elsewhere in Europe. Europe has also been struggling with mass migration from the Middle East and Africa. The ultimate effects of these events and other socio-political or geographical issues are not known but could profoundly affect global economies and markets. Additionally, in October 2023 armed conflict broke out between Israel and the militant group Hamas after Hamas infiltrated Israel’s southern border from the Gaza Strip. Israel has since declared war against Hamas and it’s possible that this conflict could escalate into a greater regional conflict. The ultimate effects of these events and other socio-political or geographical issues are not known but could profoundly affect global economies and markets. The ongoing trade war between China and the United States, including the imposition of tariffs by each country on the other country’s products, has created a tense political environment. These actions may trigger a significant reduction in international trade, the oversupply of certain manufactured goods, substantial price reductions of goods and possible failure of individual companies and/or large segments of China’s export industry, which could have a negative impact on the Fund’s performance. U.S. companies that source material and goods from China and those that make large amounts of sales in China would be particularly vulnerable to an escalation of trade tensions. Uncertainty regarding the outcome of the trade tensions and the potential for a trade war could cause the U.S. dollar to decline against safe haven currencies, such as the Japanese yen and the euro. Events such as these and their consequences are difficult to predict and it is unclear whether further tariffs may be imposed or other escalating actions may be taken in the future. The U.S. Federal Reserve (the “Fed”) has in the past sharply raised interest rates, and while the Fed has recently lowered the federal funds rates, it has signaled an intention to maintain relatively higher interest rates until current inflation levels re-align with the Fed’s long-term inflation target. Changing interest rate environments impact the various sectors of the economy in different ways. For example, in March 2023, the Federal Deposit Insurance Corporation (“FDIC”) was appointed receiver for each of Silicon Valley Bank and Signature Bank, the second- and third-largest bank failures in U.S. history, which failures may be attributable, in part, to rising interest rates. Bank failures may have a destabilizing impact on the broader banking industry or markets generally. The impact of these developments in the near- and long-term is unknown and could have additional adverse effects on economies, financial markets and asset valuations around the world. | ||||||||||||||
| Reverse Repurchase Agreement Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Reverse Repurchase Agreement Risk. 231 agreed upon, files for bankruptcy or becomes insolvent. The Fund may be restricted from taking normal portfolio actions during such time, could be subject to loss to the extent that the proceeds of the agreement are less than the value of securities subject to the agreement and may experience adverse tax consequences. | ||||||||||||||
| Direct Lending Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Direct Lending Risk. As part of its lending activities, the Fund may originate loans to companies that are experiencing significant financial or business difficulties, including companies involved in bankruptcy or other reorganization and liquidation proceedings. Although the terms of such financing may result in significant financial returns to the Fund, they involve a substantial degree of risk. The level of analytical sophistication, both financial and legal, necessary for successful financing to companies experiencing significant business and financial difficulties is unusually high. Different types of assets may be used as collateral for the Fund’s loans and, accordingly, the valuation of and risks associated with such collateral will vary by loan. There is no assurance that the Fund will correctly evaluate the value of the assets collateralizing the Fund’s loans or the prospects for a successful reorganization or similar action. In any reorganization or liquidation proceeding relating to a borrower that the Fund is lending money to, the Fund may lose all or part of the amounts advanced to the borrower or may be required to accept collateral with a value less than the amount of the loan advanced by the Fund to the borrower. Furthermore, in the event of a default by a borrower, the Fund may have difficulty disposing of the assets used as collateral for a loan. To the extent the Fund seeks to engage in direct lending, the Fund will be subject to enhanced risks of litigation, regulatory actions and other proceedings. As a result, the Fund may be required to pay legal fees, settlement costs, damages, penalties or other charges, any or all of which could materially adversely affect the Fund and its holdings. | ||||||||||||||
| Floating and Variable Rate Securities Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Floating and Variable Rate Securities Risk. | ||||||||||||||
| Municipal Securities Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Municipal Securities Risk. To the extent that a fund invests a significant portion of its assets in the securities of issuers located in a given state or U.S. territory, it will be disproportionally affected by political and economic conditions and developments in that state or territory and may involve greater risk than funds that invest in a larger universe of securities. In addition, economic, political or regulatory changes in that state or territory could adversely affect municipal securities issuers in that state or territory and therefore the value of a fund’s investment portfolio. | ||||||||||||||
| WhenIssued and DelayedDelivery Transactions Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | When-Issued and Delayed-Delivery Transactions Risk. | ||||||||||||||
| Limited Term and Tender Offer Risks [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Limited Term and Tender Offer Risks. The Fund may be required to dispose of portfolio investments in connection with any reduction in its outstanding leverage necessary in order to maintain its desired leverage ratios following an Eligible Tender Offer. It is likely that during the pendency of an Eligible Tender Offer, and possibly for a time thereafter, the Fund will hold a greater than normal percentage of its total assets in money market mutual funds, cash, cash equivalents, securities issued or guaranteed by the U.S. government or its instrumentalities or agencies, high quality, short-term money market instruments, short-term debt securities, certificates of deposit, bankers’ acceptances and other bank obligations, commercial paper or other liquid debt securities, which may adversely affect the Fund’s investment performance. If the tax basis for the portfolio investments sold is less than the sale proceeds, the Fund will recognize capital gains, which it will be required to distribute to Common Shareholders. In addition, the Fund’s purchase of tendered Common Shares pursuant to an Eligible Tender Offer will have tax consequences for tendering Common Shareholders and may have tax consequences for non-tendering Common Shareholders. All Common Shareholders remaining after an Eligible Tender Offer will be subject to proportionately higher expenses due to the reduction in the Fund’s total assets resulting from payment for the tendered Common Shares. Such reduction in the Fund’s total assets also may result in less investment flexibility, reduced diversification and greater volatility for the Fund, and may have an adverse effect on the Fund’s investment performance. If the Fund conducts an Eligible Tender Offer, there can be no assurance that the number of tendered Common Shares would not result in the Fund’s net assets totaling less than the Termination Threshold, in which case the Eligible Tender Offer will be terminated, no Common Shares will be repurchased pursuant to the Eligible Tender Offer and the Fund will terminate on the Termination Date. The investment adviser may have a conflict of interest in recommending to the Board of Trustees that the Fund have a continued existence without limitation of time. The Fund is not required to conduct additional tender offers following an Eligible Tender Offer and conversion to a continued existence without limitation of time. Therefore, remaining Common Shareholders may not have another opportunity to participate in a tender offer. A Fund portfolio holding default may significantly reduce net investment income and, therefore, Common Share dividends; and may prevent or inhibit the Fund from fully being able to liquidate its portfolio at or prior to the Termination Date. | ||||||||||||||
| Interest Rate Risk [Member] | |||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||
| Risk [Text Block] | Interest Rate Risk. | ||||||||||||||
| Common Shares [Member] | |||||||||||||||
| Other Annual Expenses [Abstract] | |||||||||||||||
| Basis of Transaction Fees, Note [Text Block] | As a Percentage of Net Assets Attributable to Common Shares | ||||||||||||||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |||||||||||||||
| Outstanding Security, Title [Text Block] | Common shares | ||||||||||||||
| Outstanding Security, Held [Shares] | 54,801,890 | ||||||||||||||
| At-the-Market Transaction [Member] | |||||||||||||||
| Other Annual Expenses [Abstract] | |||||||||||||||
| Expense Example, Year 01 | $ 57 | ||||||||||||||
| Expense Example, Years 1 to 3 | 151 | ||||||||||||||
| Expense Example, Years 1 to 5 | 246 | ||||||||||||||
| Expense Example, Years 1 to 10 | $ 485 | ||||||||||||||
| [1]The maximum sales charge for offerings made at-the-market is 1.00%. If the Common Shares are sold to or through underwriters in an offering that is not made at-the-market, the applicable Prospectus Supplement will set forth any other applicable sales load and the estimated offering expenses. Fund shareholders will pay all offering expenses involved with an offering.[2]You will be charged a $2.50 service charge and pay brokerage charges if you direct Computershare Inc. and Computershare Trust Company, N.A., as agent for the common shareholders, to sell your Common Shares held in a dividend reinvestment account.[3]Stated as percentages of average net assets attributable to Common Shares for the fiscal year ended October 31, 2024.[4]Interest and Other Related Expenses reflect actual expenses and fees for leverage incurred by a Fund for the fiscal year ended October 31, 2024. The types of leverage used by the Fund during the fiscal year ended October 31, 2024 are described in the Fund Leverage and the Notes to Financial Statements sections of this annual report. Actual Interest and Other Related Expenses incurred in the future may be higher or lower. If short-term market interest rates rise in the future, and if the Fund continues to maintain leverage, the cost of which is tied to short-term interest rates, the Fund’s interest expenses on its short-term borrowings can be expected to rise in tandem. The Fund’s use of leverage will increase the amount of management fees paid to the Fund’s adviser and sub-advisor(s).[5]Other Expenses are based on estimated amounts for the current fiscal year. Expenses attributable to the Fund’s investments, if any, in other investment companies are currently estimated not to exceed 0.01%.[6]Aggregate Amount Outstanding: Aggregate amount outstanding represents the principal amount outstanding or liquidation preference, if applicable, as of the end of the relevant fiscal year and does not include any preferred shares noticed for redemption as noted on the Statement of Assets and Liabilities, if applicable.[7]Asset Coverage Per $100,000: Asset coverage per $100,000 is calculated by subtracting the Fund’s liabilities and indebtedness not represented by senior securities from the Fund’s total assets, dividing the result by the aggregate amount of the Fund’s senior securities representing indebtedness then outstanding (if applicable), plus the aggregate of the involuntary liquidation preference of the outstanding preferred shares, if applicable, and multiplying the result by 100,000.[8]For the period September 16, 2019 (commencement of operations) through October 31, 2019. | |||||||||||||||
