| N-2 - USD ($) | 3 Months Ended | 12 Months Ended | ||||||||||||||||||||||||||||||||||||||
| Jul. 31, 2023 | Jul. 31, 2022 | Aug. 31, 2021 | Aug. 31, 2020 | Aug. 31, 2019 | Aug. 31, 2018 | Aug. 31, 2017 | Aug. 31, 2016 | Aug. 31, 2015 | Aug. 31, 2014 | Aug. 31, 2013 | Jul. 31, 2023 | Apr. 30, 2023 | Jan. 31, 2023 | Oct. 31, 2022 | Jul. 31, 2022 | May 31, 2022 | Feb. 28, 2022 | Nov. 30, 2021 | Aug. 31, 2021 | May 31, 2021 | Feb. 26, 2021 | Nov. 30, 2020 | Jul. 31, 2023 | |||||||||||||||||
| Cover [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Entity Central Index Key | 0001176194 | |||||||||||||||||||||||||||||||||||||||
| Amendment Flag | false | |||||||||||||||||||||||||||||||||||||||
| Document Type | N-CSR | |||||||||||||||||||||||||||||||||||||||
| Entity Registrant Name | BlackRock Municipal Income Trust II | |||||||||||||||||||||||||||||||||||||||
| Fee Table [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Shareholder Transaction Expenses [Table Text Block] | BLE Shareholder Transaction Expenses Maximum sales load (as a percentage of offering price) (a) 1.00 % Offering expenses borne by the Trust (as a percentage of offering price) (a) 0.02 % $0.02 per share Dividend reinvestment plan fees common shares (b) Dividend reinvestment plan sale transaction fee $2.50 (b) (a) BLE shareholders will pay all offering expenses involved with this offering. (b) Computershare Trust Company, N.A.’s (the “Reinvestment Plan Agent”) fees for the handling of the reinvestment of dividends will be paid by BLE. However, shareholders will pay a $0.02 per share fee incurred in connection with open-market purchases, which will be deducted from the value of the dividend. Shareholders will also be charged a $2.50 sales fee and pay a $0.15 per share fee if direct the Reinvestment Plan Agent to sell the common shares held in a dividend reinvestment account. Per share fees include any applicable brokerage commissions the Reinvestment Plan Agent is required to pay. | |||||||||||||||||||||||||||||||||||||||
| Sales Load [Percent] | [1] | 1% | ||||||||||||||||||||||||||||||||||||||
| Dividend Reinvestment and Cash Purchase Fees | [2] | $ 0.02 | ||||||||||||||||||||||||||||||||||||||
| Other Transaction Expenses [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Other Transaction Expenses [Percent] | [1] | 0.02% | ||||||||||||||||||||||||||||||||||||||
| Annual Expenses [Table Text Block] | Estimated Annual Expenses Investment advisory fees (c)(d) 0.90 % Other expenses 2.53 Miscellaneous 0.06 Interest expense (e) 2.47 Acquired fund fees and expenses (f) 0.01 Total annual expenses (f) 3.44 Fee waivers (d) — Total annual Trust operating expenses after fee waivers (d) 3.44 (c) BLE currently pays the Manager a monthly fee at an annual contractual investment management fee rate of 0.55% of its average weekly managed assets. For purposes of calculating these fees, “managed assets” means the total assets of BLE (including any assets attributable to money borrowed for investment purposes) minus the sum of its accrued liabilities (other than money borrowed for investment purposes). (d) BLE and the Manager have entered into a fee waiver agreement (the “Fee Waiver Agreement”), pursuant to which the Manager has contractually agreed to waive the management fee with respect to any portion of BLE’s assets attributable to investments in any equity and fixed-income mutual funds and exchange-traded funds managed by the Manager or its affiliates that have a contractual management fee, through June 30, 2025. In addition, pursuant to the Fee Waiver Agreement, the Manager has contractually agreed to waive its management fees by the amount of investment advisory fees BLE pays to the Manager indirectly through its investment in money market funds managed by the Manager or its affiliates, through June 30, 2025. The Fee Waiver Agreement may be terminated at any time, without the payment of any penalty, only by BLE (upon the vote of a majority of the Trustees who are not “interested persons” (as defined in the Investment Company Act) of the Trust or a majority of the outstanding voting securities of BLE), upon 90 days’ written notice by BLE to the Manager. (e) Assumes the use of leverage in the form of tender option bond transactions and preferred shares representing 37% of Managed Assets at an annual cost of leverage to BLE of 3.88%, which is based on current market conditions. The actual amount of interest expense borne by BLE will vary over time in accordance with the level of BLE’s use of tender option bond transactions and variations in market interest rates, as well as preferred shares transactions and changes to agreement terms with counterparties. Interest expense is required to be treated as an expense of BLE for accounting purposes. BLE uses leverage to seek to enhance its returns to common shareholders. This leverage generally takes two forms: the issuance of VMTP Shares and investment in TOBs. Both forms of leverage benefit common shareholders if the cost of the leverage is lower than the returns earned by BLE when it invests the proceeds from the leverage. In order to help you better understand the costs associated with BLE’s leverage strategy, the total annual Trust operating expenses after fee waivers (excluding interest expense) are 0.97%. (f) The total annual expenses do not correlate to the ratios to average net assets shown in BLE’s Financial Highlights for the year ended July 31, 2023, which do not include acquired fund fees and expenses. | |||||||||||||||||||||||||||||||||||||||
| Management Fees [Percent] | [3],[4] | 0.90% | ||||||||||||||||||||||||||||||||||||||
| Acquired Fund Fees and Expenses [Percent] | [5] | 0.01% | ||||||||||||||||||||||||||||||||||||||
| Other Annual Expenses [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Other Annual Expense 1 [Percent] | [6] | 0.06% | ||||||||||||||||||||||||||||||||||||||
| Other Annual Expense 2 [Percent] | [5] | 2.47% | ||||||||||||||||||||||||||||||||||||||
| Other Annual Expenses [Percent] | 2.53% | |||||||||||||||||||||||||||||||||||||||
| Total Annual Expenses [Percent] | 3.44% | |||||||||||||||||||||||||||||||||||||||
| Waivers and Reimbursements of Fees [Percent] | ||||||||||||||||||||||||||||||||||||||||
| Net Expense over Assets [Percent] | 3.44% | |||||||||||||||||||||||||||||||||||||||
| Expense Example [Table Text Block] | The following example illustrates BLE’s expenses (including the sales load of $10.00 and offering costs of $0.23) that shareholders would pay on a $1,000 investment in common shares, assuming (i) total net annual expenses of 3.44% of net assets attributable to common shares and (ii) a 5% annual return: 1 Year 3 Years 5 Years 10 Years Total expenses incurred $ 45 $ 115 $ 187 $ 378 | |||||||||||||||||||||||||||||||||||||||
| Expense Example, Year 01 | $ 45 | |||||||||||||||||||||||||||||||||||||||
| Expense Example, Years 1 to 3 | 115 | |||||||||||||||||||||||||||||||||||||||
| Expense Example, Years 1 to 5 | 187 | |||||||||||||||||||||||||||||||||||||||
| Expense Example, Years 1 to 10 | $ 378 | |||||||||||||||||||||||||||||||||||||||
| Purpose of Fee Table , Note [Text Block] | The following table and example are intended to assist shareholders in understanding the various costs and expenses directly or indirectly associated with investing in BLE’s common shares. | |||||||||||||||||||||||||||||||||||||||
| Basis of Transaction Fees, Note [Text Block] | as a percentage of offering price | |||||||||||||||||||||||||||||||||||||||
| Management Fee not based on Net Assets, Note [Text Block] | BLE currently pays the Manager a monthly fee at an annual contractual investment management fee rate of 0.55% of its average weekly managed assets. For purposes of calculating these fees, “managed assets” means the total assets of BLE (including any assets attributable to money borrowed for investment purposes) minus the sum of its accrued liabilities (other than money borrowed for investment purposes). | |||||||||||||||||||||||||||||||||||||||
| Acquired Fund Total Annual Expenses, Note [Text Block] | (f) The total annual expenses do not correlate to the ratios to average net assets shown in BLE’s Financial Highlights for the year ended July 31, 2023, which do not include acquired fund fees and expenses. | |||||||||||||||||||||||||||||||||||||||
| Financial Highlights [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Senior Securities [Table Text Block] | Fiscal Year Ended Total Amount Asset Liquidation (a) Average (000 ) Type of July 31, 2023 $ 33,812 $ 27,213 (b) $ N/A $ 64,345 (c) TOBs July 31, 2023 302,700 273,428 (d) 100,000 N/A VMTP Shares July 31, 2022 113,752 9,073 (b) N/A 134,008 (c) TOBs July 31, 2022 302,700 247,830 (d) 100,000 N/A VMTP Shares August 31, 2021 302,700 343,975 (e) 100,000 N/A VMTP Shares August 31, 2020 151,300 330,223 (e) 100,000 N/A VMTP Shares August 31, 2019 151,300 335,723 (e) 100,000 N/A VMTP Shares August 31, 2018 151,300 326,330 (e) 100,000 N/A VMTP Shares August 31, 2017 151,300 335,890 (e) 100,000 N/A VMTP Shares August 31, 2016 151,300 350,213 (e) 100,000 N/A VMTP Shares August 31, 2015 151,300 336,529 (e) 100,000 N/A VMTP Shares August 31, 2014 151,300 339,946 (e) 100,000 N/A VMTP Shares August 31, 2013 151,300 306,430 (e) 100,000 N/A VMTP Shares (a) Represents the amount to which a holder of preferred shares would be entitled upon the liquidation of VMTP Shares in preference to common shareholders, expressed as a dollar amount per preferred share. VMTP Shares are considered debt of the issuer; therefore, the liquidation preference approximates fair value. (b) Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares and TOBs) from the Trust’s total assets and dividing this by the amount of TOBs, and by multiplying the results by 1,000. (c) Represents weighted average daily market value of TOBs. (d) Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares and TOBs) from the Trust’s total assets and dividing this by the sum of the amount of TOBs and liquidation value of the VMTP Shares, and by multiplying the results by 100,000. Effective July 18, 2022, TOB Trust Certificates are treated as senior securities pursuant to Rule 18f-4 of the 1940 Act. (e) Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares) from the Trust’s total assets and dividing this by the liquidation value of the VMTP Shares, and by multiplying the results by 100,000. | |||||||||||||||||||||||||||||||||||||||
| Senior Securities, Note [Text Block] | Senior Securities The following table sets forth information regarding BLE’s outstanding senior securities as of the end of each of BLE’s last ten fiscal years, as applicable. BLE’s audited financial statements, including Deloitte & Touche LLP’s Report of Independent Registered Public Accounting Firm, and accompanying notes to financial statements, are included in this annual report. Fiscal Year Ended Total Amount Asset Liquidation (a) Average (000 ) Type of July 31, 2023 $ 33,812 $ 27,213 (b) $ N/A $ 64,345 (c) TOBs July 31, 2023 302,700 273,428 (d) 100,000 N/A VMTP Shares July 31, 2022 113,752 9,073 (b) N/A 134,008 (c) TOBs July 31, 2022 302,700 247,830 (d) 100,000 N/A VMTP Shares August 31, 2021 302,700 343,975 (e) 100,000 N/A VMTP Shares August 31, 2020 151,300 330,223 (e) 100,000 N/A VMTP Shares August 31, 2019 151,300 335,723 (e) 100,000 N/A VMTP Shares August 31, 2018 151,300 326,330 (e) 100,000 N/A VMTP Shares August 31, 2017 151,300 335,890 (e) 100,000 N/A VMTP Shares August 31, 2016 151,300 350,213 (e) 100,000 N/A VMTP Shares August 31, 2015 151,300 336,529 (e) 100,000 N/A VMTP Shares August 31, 2014 151,300 339,946 (e) 100,000 N/A VMTP Shares August 31, 2013 151,300 306,430 (e) 100,000 N/A VMTP Shares (a) Represents the amount to which a holder of preferred shares would be entitled upon the liquidation of VMTP Shares in preference to common shareholders, expressed as a dollar amount per preferred share. VMTP Shares are considered debt of the issuer; therefore, the liquidation preference approximates fair value. (b) Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares and TOBs) from the Trust’s total assets and dividing this by the amount of TOBs, and by multiplying the results by 1,000. (c) Represents weighted average daily market value of TOBs. (d) Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares and TOBs) from the Trust’s total assets and dividing this by the sum of the amount of TOBs and liquidation value of the VMTP Shares, and by multiplying the results by 100,000. Effective July 18, 2022, TOB Trust Certificates are treated as senior securities pursuant to Rule 18f-4 of the 1940 Act. (e) Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares) from the Trust’s total assets and dividing this by the liquidation value of the VMTP Shares, and by multiplying the results by 100,000. | |||||||||||||||||||||||||||||||||||||||
| Senior Securities Headings, Note [Text Block] | The following table sets forth information regarding BLE’s outstanding senior securities as of the end of each of BLE’s last ten fiscal years, as applicable. BLE’s audited financial statements, including Deloitte & Touche LLP’s Report of Independent Registered Public Accounting Firm, and accompanying notes to financial statements, are included in this annual report. | |||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Investment Objectives and Practices [Text Block] | The Fund’s investment objective is to provide current income exempt from regular federal income taxes. As a fundamental policy, under normal market conditions, the Fund will invest at least 80% of its managed assets in municipal obligations issued by or on behalf of states, territories and possessions of the United States and their political subdivisions, agencies or instrumentalities (“Municipal Bonds”), the interest of which is exempt from regular federal income tax (except that the interest may be subject to the alternative minimum tax). The Fund may invest directly in securities or synthetically through the use of derivatives. The Fund cannot change its investment objectives or the foregoing fundamental policy without the approval of the holders of a majority of the outstanding common shares and the outstanding preferred shares, including the variable rate muni term preferred shares (“VMTP Shares”), voting together as a single class, and of the holders of a majority of the outstanding preferred shares, including the VMTP Shares, voting as a separate class. A majority of the outstanding means (1) 67% or more of the shares present at a meeting, if the holders of more than 50% of the outstanding shares are present or represented by proxy, or (2) more than 50% of the outstanding shares, whichever is less. The Fund’s investment policies provide that, under normal market conditions, the Fund will invest at least 80% of its managed assets in investment grade quality Municipal Bonds. Investment grade quality means that such bonds are rated, at the time of investment, within the four highest grades (Baa or BBB or better by Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”), or Fitch Ratings, Inc. (“Fitch”)) or are unrated but judged to be of comparable quality by BlackRock Advisors, LLC (the “Manager”). Municipal Bonds rated Baa by Moody’s are investment grade, but Moody’s considers Municipal Bonds rated Baa to have speculative characteristics. Changes in economic conditions or other circumstances are more likely to lead to a weakened capacity for issuers of Municipal Bonds that are rated BBB or Baa (or that have equivalent ratings) to make principal and interest payments than is the case for issuers of higher grade Municipal Bonds. In the case of short-term notes, the investment grade rating categories are SP-1+ through SP-2 for S&P, MIG-1 through MIG-3 for Moody’s and F-1+ through F-3 for Fitch. In the case of tax exempt commercial paper, the investment grade rating categories are A-1+ through A-3 for S&P, Prime-1 through Prime-3 for Moody’s and F-1+ through F-3 for Fitch. Obligations ranked in the lowest investment grade rating category (BBB, SP-2 and A-3 for S&P; Baa, MIG-3 and Prime-3 for Moody’s and BBB and F-3 for Fitch), while considered “investment grade,” may have certain speculative characteristics. There may be sub-categories or gradations indicating relative standing within the rating categories set forth above. In assessing the quality of Municipal Bonds with respect to the foregoing requirements, the Manager takes into account the nature of any letters of credit or similar credit enhancement to which particular Municipal Bonds are entitled and the creditworthiness of the financial institution that provided such credit enhancement. The Fund may invest up to 20% of its managed assets in Municipal Bonds that are rated, at the time of investment, Ba/BB or B by Moody’s, S&P or Fitch or that are unrated but judged to be of comparable quality by the Manager. Bonds of below investment grade quality are regarded as having predominantly speculative characteristics with respect to the issuer’s capacity to pay interest and repay principal. Such securities are sometimes referred to as “high yield” or “junk” bonds. The foregoing credit quality policies apply only at the time a security is purchased, and the Fund is not required to dispose of a security if a rating agency downgrades its assessment of the credit characteristics of a particular issue. In determining whether to retain or sell a security that a rating agency has downgraded, the Manager may consider such factors as the Manager’s assessment of the credit quality of the issuer of the security, the price at which the security could be sold and the rating, if any, assigned to the security by other rating agencies. In the event that the Fund disposes of a portfolio security subsequent to its being downgraded, the Fund may experience a greater risk of loss than if such security had been sold prior to such downgrade. The Fund may also invest in securities of other open- or closed-end investment companies that invest primarily in Municipal Bonds of the types in which the Fund may invest directly and in tax-exempt preferred shares that pay dividends that are exempt from regular federal income tax. In addition, the Fund may purchase Municipal Bonds that are additionally secured by insurance, bank credit agreements or escrow accounts. The credit quality of companies which provide these credit enhancements will affect the value of those securities. Although the insurance feature reduces certain financial risks, the premiums for insurance and the higher market price paid for insured obligations may reduce the Fund’s income. The insurance feature does not guarantee the market value of the insured obligations or the net asset value of the common shares. The Fund may purchase insured bonds and may purchase insurance for bonds in its portfolio. The Fund may invest in certain tax exempt securities classified as “private activity bonds” (or industrial development bonds, under pre-1986 law) (in general, bonds that benefit non-governmental entities) that may subject certain investors in the Fund to an alternative minimum tax. The percentage of the Fund’s total assets invested in private activity bonds will vary from time to time. The Fund has not established any limit on the percentage of its portfolio that may be invested in Municipal Bonds subject to the alternative minimum tax provisions of federal tax law, and the Fund expects that a portion of the income it produces will be includable in alternative minimum taxable income. VMTP Shares therefore would not ordinarily be a suitable investment for investors who are subject to the federal alternative minimum tax or who would become subject to such tax by purchasing VMTP Shares. The suitability of an investment in VMTP Shares will depend upon a comparison of the after-tax yield likely to be provided from the Fund with that from comparable tax-exempt investments not subject to the alternative minimum tax, and from comparable fully taxable investments, in light of each such investor’s tax position. Special considerations may apply to corporate investors. The average maturity of the Fund’s portfolio securities varies from time to time based upon an assessment of economic and market conditions by the Manager. The Fund’s portfolio at any given time may include both long- term and intermediate-term Municipal Bonds. The Fund’s stated expectation is that it will invest in Municipal Bonds that, in the Manager’s opinion, are underrated or undervalued. Underrated Municipal Bonds are those whose ratings do not, in the opinion of the Manager, reflect their true higher creditworthiness. Undervalued Municipal Bonds are bonds that, in the opinion of the Manager, are worth more than the value assigned to them in the marketplace. The Manager may at times believe that bonds associated with a particular municipal market sector (for example, but not limited to electric utilities), or issued by a particular municipal issuer, are undervalued. The Manager may purchase those bonds for the Fund’s portfolio because they represent a market sector or issuer that the Manager considers undervalued, even if the value of those particular bonds appears to be consistent with the value of similar bonds. Municipal Bonds of particular types (for example, but not limited to hospital bonds, industrial revenue bonds or bonds issued by a particular municipal issuer) may be undervalued because there is a temporary excess of supply in that market sector, or because of a general decline in the market price of Municipal Bonds of the market sector for reasons that do not apply to the particular Municipal Bonds that are considered undervalued. The Fund’s investment in underrated or undervalued Municipal Bonds will be based on the Manager’s belief that their yield is higher than that available on bonds bearing equivalent levels of interest rate risk, credit risk and other forms of risk, and that their prices will ultimately rise, relative to the market, to reflect their true value. Any capital appreciation realized by the Fund will generally result in capital gain distributions subject to federal capital gains taxation. The Fund ordinarily does not intend to realize significant investment income not exempt from federal income tax. From time to time, the Fund may realize taxable capital gains. Federal tax legislation has limited the types and volume of bonds the interest on which qualifies for a federal income tax exemption. As a result, this legislation and legislation that may be enacted in the future may affect the availability of Municipal Bonds for investment by the Fund. Leverage: The Fund may enter into reverse repurchase agreements with respect to its portfolio investments subject to the Fund’s investment restrictions. The Fund reserves the right to borrow funds subject to the Fund’s investment restrictions. The proceeds of borrowings may be used for any valid purpose including, without limitation, liquidity, investments and repurchases of shares of the Fund. | |||||||||||||||||||||||||||||||||||||||
| Risk Factors [Table Text Block] | 9. PRINCIPAL RISKS In the normal course of business, the Trusts invest in securities or other instruments and may enter into certain transactions, and such activities subject each Trust to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues, recessions, or other events could have a significant impact on the Trusts and their investments. The Trusts may hold a significant amount of bonds subject to calls by the issuers at defined dates and prices. When bonds are called by issuers and the Trusts reinvest the proceeds received, such investments may be in securities with lower yields than the bonds originally held, and correspondingly, could adversely impact the yield and total return performance of a Trust. A Trust structures and “sponsors” the TOB Trusts in which it holds TOB Residuals and has certain duties and responsibilities, which may give rise to certain additional risks including, but not limited to, compliance, securities law and operational risks. As short-term interest rates rise, the Trusts’ investments in the TOB Trusts may adversely affect the Trusts’ net investment income and dividends to Common Shareholders. Also, fluctuations in the market value of municipal bonds deposited into the TOB Trust may adversely affect the Trusts’ NAVs per share. The U.S. Securities and Exchange Commission (“SEC”) and various federal banking and housing agencies have adopted credit risk retention rules for securitizations (the “Risk Retention Rules”). The Risk Retention Rules would require the sponsor of a TOB Trust to retain at least 5% of the credit risk of the underlying assets supporting the TOB Trust’s municipal bonds. The Risk Retention Rules may adversely affect the Trusts’ ability to engage in TOB Trust transactions or increase the costs of such transactions in certain circumstances. TOB Trusts constitute an important component of the municipal bond market. Any modifications or changes to rules governing TOB Trusts may adversely impact the municipal market and the Trusts, including through reduced demand for and liquidity of municipal bonds and increased financing costs for municipal issuers. The ultimate impact of any potential modifications on the TOB Trust market and the overall municipal market is not yet certain. Illiquidity Risk: Market Risk: Municipal securities are subject to the risk that litigation, legislation or other political events, local business or economic conditions, credit rating downgrades, or the bankruptcy of the issuer could have a significant effect on an issuer’s ability to make payments of principal and/or interest or otherwise affect the value of such securities. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to, taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the discontinuance of the tax benefits supporting the project or assets or the inability to collect revenues for the project or from the assets. Municipal securities may be less liquid than taxable bonds, and there may be less publicly available information on the financial condition of municipal security issuers than for issuers of other securities. Infectious Illness Risk: Counterparty Credit Risk: A derivative contract may suffer a mark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract. With exchange-traded futures, there is less counterparty credit risk to the Trusts since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, a Trust does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Trusts. Geographic/Asset Class Risk: The Trusts invest a significant portion of their assets in securities within a single or limited number of market sectors. When a fund concentrates its investments in this manner, it assumes the risk that economic, regulatory, political and social conditions affecting such sectors may have a significant impact on the Trust and could affect the income from, or the value or liquidity of, the Trust’s portfolio. Investment percentages in specific sectors are presented in the Schedules of Investments. Certain Trusts invest a significant portion of their assets in high yield securities. High yield securities that are rated below investment-grade (commonly referred to as “junk bonds”) or are unrated may be deemed speculative, involve greater levels of risk than higher-rated securities of similar maturity and are more likely to default. High yield securities may be issued by less creditworthy issuers, and issuers of high yield securities may be unable to meet their interest or principal payment obligations. High yield securities are subject to extreme price fluctuations, may be less liquid than higher rated fixed-income securities, even under normal economic conditions, and frequently have redemption features. The Trusts invest a significant portion of their assets in fixed-income securities and/or use derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and other fixed-income securities will decrease as interest rates rise and increase as interest rates fall. The Trusts may be subject to a greater risk of rising interest rates due to the period of historically low interest rates that ended in March 2022. The Federal Reserve has recently been raising the federal funds rate as part of its efforts to address inflation. There is a risk that interest rates will continue to rise, which will likely drive down the prices of bonds and other fixed-income securities, and could negatively impact the Trusts’ performance. The Trusts invest a significant portion of their assets in securities of issuers located in the United States. A decrease in imports or exports, changes in trade regulations, inflation and/or an economic recession in the United States may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the United States may also have a significant effect on U.S. markets generally, as well as on the value of certain securities. Governmental agencies project that the United States will continue to maintain elevated public debt levels for the foreseeable future which may constrain future economic growth. Circumstances could arise that could prevent the timely payment of interest or principal on U.S. government debt, such as reaching the legislative “debt ceiling.” Such non-payment would result in substantial negative consequences for the U.S. economy and the global financial system. If U.S. relations with certain countries deteriorate, it could adversely affect issuers that rely on the United States for trade. The United States has also experienced increased internal unrest and discord. If these trends were to continue, they may have an adverse impact on the U.S. economy and the issuers in which the Trusts invest. Risk Factors This section contains a discussion of the general risks of investing in each Fund. The net asset value and market price of, and dividends paid on, the common shares will fluctuate with and be affected by, among other things, the risks more fully described below. As with any fund, there can be no guarantee that the Fund will meet its investment objective or that the Fund’s performance will be positive for any period of time. Each risk noted below is applicable to each Fund unless the specific Fund or Funds are noted in a parenthetical. The order of the below risk factors does not indicate the significance of any particular risk factor. Investment and Market Discount Risk: could decrease as a result of its investment activities. At any point in time an investment in the Fund’s common shares may be worth less than the original amount invested, even after taking into account distributions paid by the Fund. During periods in which the Fund may use leverage, the Fund’s investment, market discount and certain other risks will be magnified. Debt Securities Risk: • Interest Rate Risk — The market value of bonds and other fixed-income securities changes in response to interest rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Fund may be subject to a greater risk of rising interest rates due to the recent period of historically low interest rates. For example, if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being equal, the value of the Fund’s investments would be expected to decreaseby10%. (Duration is a measure of the price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.)The magnitude of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund management. To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities. These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in value when interest rates change. A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could hurt the Fund’s performance. • Credit Risk — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. • Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these obligations to fall. • Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. Municipal Securities Risks: • General Obligation Bonds Risks — Timely payments depend on the issuer’s credit quality, ability to raise tax revenues and ability to maintain an adequate tax base. • Revenue Bonds Risks — These payments depend on the money earned by the particular facility or class of facilities, or the amount of revenues derived from another source. • Private Activity Bonds Risks — Municipalities and other public authorities issue private activity bonds to finance development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment. The Fund’s investments may consist of private activity bonds that may subject certain shareholders to an alternative minimum tax. • Moral Obligation Bonds Risks — Moral obligation bonds are generally issued by special purpose public authorities of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral commitment, but not a legal obligation, of the state or municipality. • Municipal Notes Risks — Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the anticipated proceeds, the notes may not be fully repaid and the Fund may lose money. • Municipal Lease Obligations Risks — In a municipal lease obligation, the issuer agrees to make payments when due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease obligation, the lease obligation is secured by the leased property. • Tax-Exempt Status Risk — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds and payments under derivative securities. Neither the Fund nor its investment manager will independently review the bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its shareholders to substantial tax liabilities. Taxability Risk: Insurance Risk: Junk Bonds Risk: U.S. Government Obligations Risk: Leverage Risk: The use of leverage creates an opportunity for increased common share net investment income dividends, but also creates risks for the holders of common shares. The Fund cannot assure you that the use of leverage will result in a higher yield on the common shares. Any leveraging strategy the Fund employs may not be successful. Leverage involves risks and special considerations for common shareholders, including: • the likelihood of greater volatility of net asset value, market price and dividend rate of the common shares than a comparable portfolio without leverage; • the risk that fluctuations in interest rates or dividend rates on any leverage that the Fund must pay will reduce the return to the common shareholders; • the effect of leverage in a declining market, which is likely to cause a greater decline in the net asset value of the common shares than if the Fund were not leveraged, which may result in a greater decline in the market price of the common shares; • leverage may increase operating costs, which may reduce total return. Any decline in the net asset value of the Fund’s investments will be borne entirely by the holders of common shares. Therefore, if the market value of the Fund’s portfolio declines, leverage will result in a greater decrease in net asset value to the holders of common shares than if the Fund were not leveraged. This greater net asset value decrease will also tend to cause a greater decline in the market price for the common shares. Tender Option Bonds Risk: Reverse Repurchase Agreements Risk: Illiquid Investments Risk: 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. Privately issued debt securities are often of below investment grade quality, frequently are unrated and present many of the same risks as investing in below investment grade public debt securities. Investment Companies and ETFs Risk (BLE): The securities of other investment companies and ETFs in which the Fund may invest may be leveraged. As a result, the Fund may be indirectly exposed to leverage through an investment in such securities. An investment in securities of other investment companies and ETFs that use leverage may expose the Fund to higher volatility in the market value of such securities and the possibility that the Fund’s long-term returns on such securities (and, indirectly, the long-term returns of shares of the Fund) will be diminished. As with other investments, investments in other investment companies, including ETFs, are subject to market and selection risk. To the extent the Fund is held by an affiliated fund, the ability of the Fund itself to hold other investment companies may be limited. Derivatives Risk: • Leverage Risk — The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market movements may result in large changes in the value of a derivatives position and can result in losses that greatly exceed the amount originally invested. • Market Risk — Some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally, the Manager may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s derivatives positions to lose value. • Counterparty Risk — Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated exposure to such a counterparty. • Illiquidity Risk — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. • Operational Risk — The use of derivatives includes the risk of potential operational issues, including documentation issues, settlement issues, systems failures, inadequate controls and human error. • Legal Risk — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or enforceability of a contract. • Volatility and Correlation Risk — Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate with the overall securities markets. • Valuation Risk — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to purchase complex instruments or quote prices for them. • Hedging Risk — Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging may result in certain adverse tax consequences. • Tax Risk — Certain aspects of the tax treatment of derivative instruments, including swap agreements and commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund realizes from its investments. Risk of Investing in the United States: Market Risk and Selection Risk: An outbreak of an infectious coronavirus (COVID-19) that was first detected in December 2019 developed into a global pandemic that has resulted in numerous disruptions in the market and has had significant economic impact leaving general concern and uncertainty. Although vaccines have been developed and approved for use by various governments, the duration of the pandemic and its effects cannot be predicted with certainty. The impact of this coronavirus, and other epidemics and pandemics that may arise in the future, could affect the economies of many nations, individual companies and the market in general ways that cannot necessarily be foreseen at the present time. | |||||||||||||||||||||||||||||||||||||||
| Share Price [Table Text Block] | Share Price Data The following table summarizes BLE’s highest and lowest daily closing market prices on the NYSE per common share, the NAV per common share, and the premium to or discount from NAV, on the date of each of the high and low market prices. The trading volume indicates the number of common shares traded on the NYSE during the respective quarters. Effective July 31, 2022, BLE changed the its fiscal year end from August 31 to July 31. NYSE Market Price NAV per Common Premium/ During Quarter Ended High Low High Low High Low Trading Volume July 31, 2023 $ 10.54 $ 9.96 $ 12.17 $ 11.69 (13.39 )% (14.80 )% 6,080,318 April 30, 2023 11.06 10.25 12.38 11.72 (10.66 ) (12.54 ) 6,088,596 January 31, 2023 11.09 9.49 12.29 10.82 (9.76 ) (12.29 ) 11,943,475 October 31, 2022 11.95 9.43 12.60 10.64 (5.16 ) (11.37 ) 9,345,902 July 31, 2022 11.86 10.57 12.78 11.78 (7.20 ) (10.27 ) 5,099,259 May 31, 2022 13.90 10.63 14.14 11.72 (1.70 ) (9.30 ) 11,216,795 February 28, 2022 15.38 13.65 15.03 14.10 2.33 (3.19 ) 8,082,836 November 30, 2021 16.14 14.86 15.18 14.96 6.32 (0.67 ) 4,325,591 August 31, 2021 16.10 15.35 15.18 15.18 6.06 1.12 4,954,334 May 31, 2021 15.83 14.78 15.18 14.82 5.46 (0.67 ) 5,273,595 February 26, 2021 16.16 15.00 15.46 14.83 4.53 (0.07 ) 2,122,958 November 30, 2020 15.66 14.28 14.98 14.51 6.10 (1.65 ) 2,112,424 As of July 31, 2023, BLE’s market price, NAV per Common Share, and premium/(discount) to NAV per Common Share were $10.45, $12.09, and (13.56)%, respectively. Common shares of BLE have historically traded at both a premium and discount to NAV. Shares of closed-end funds frequently trade at a discount to their NAV. Because of this possibility and the recognition that any such discount may not be in the interest of shareholders, the Board might consider from time to time engaging in open-market repurchases, managed distribution plans, or other programs intended to reduce the discount. We cannot guarantee or assure, however, that the Board will decide to engage in any of these actions. Nor is there any guarantee or assurance that such actions, if undertaken, would result in the shares trading at a price equal or close to the NAV. | |||||||||||||||||||||||||||||||||||||||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Capital Stock [Table Text Block] | 10. CAPITAL SHARE TRANSACTIONS BYM and BLE are authorized to issue an unlimited number of shares, including Preferred Shares, par value $0.001 per share, all of which were initially classified as Common Shares. The Board is authorized, however, to reclassify any unissued Common Shares to Preferred Shares without the approval of Common Shareholders. MVF is authorized to issue 160 million shares, 150 million of which were initially classified as Common Shares, par value $0.10 per share and 10 million of which were classified as Preferred Shares, par value $0.10 per share. Common Shares For the periods shown, shares issued and outstanding increased by the following amounts as a result of dividend reinvestment: Trust Name Year Ended Period from Year Ended BYM 6,598 4,409 4,589 BLE — 24,988 39,663 For the period ended July 31, 2022, shares issued and outstanding increased by 24,988 as a result of dividend reinvestment and 177,680 from the Shelf Offering for BLE. For the period ended July 31, 2022 and year ended August 31, 2021, shares issued and outstanding remained constant for MVF. For the year ended August 31, 2021, Common Shares of BLE issued and outstanding increased by 25,061,561 as a result of the reorganization of BSD, MFT and BBF with and into BLE. For the year ended August 31, 2021, Common Shares of BLE issued and outstanding decreased by 25 as a result of a redemption of fractional shares from the reorganization of BSD, MFT and BBF with and into BLE. The Trusts participate in an open market share repurchase program (the “Repurchase Program”). From December 1, 2021 through November 30, 2022, each Trust may repurchase up to 5% of its outstanding common shares under the Repurchase Program, based on common shares outstanding as of the close of business on November 30, 2021, subject to certain conditions. From December 1, 2022 through November 30, 2023, each Trust may repurchase up to 5% of its outstanding common shares under the Repurchase Program, based on common shares outstanding as of the close of business on November 30, 2022, subject to certain conditions. The Repurchase Program has an accretive effect as shares are purchased at a discount to the Trust’s NAV. There is no assurance that the Trusts will purchase shares in any particular amounts. The total cost of the shares repurchased is reflected in Trusts’ Statements of Changes in Net Assets. For the periods shown, shares repurchased and cost, including transaction costs, were as follows: BYM Shares Amounts Year Ended July 31, 2023 191,145 $ 2,148,748 BLE Shares Amounts Year Ended July 31, 2023 583,612 $ 6,114,272 MVF Shares Amounts Year Ended July 31, 2023 785,973 $ 5,324,949 BLE has filed a prospectus with the SEC allowing it to issue an additional 15,000,000 Common Shares through the Shelf Offering. Under the Shelf Offering, BLE, subject to market conditions, may raise additional equity capital from time to time in varying amounts and utilizing various offering methods at a net price at or above each Trust’s NAV per Common Share (calculated within 48 hours of pricing). As of period end, 14,822,320 Common Shares remain available for issuance under the Shelf Offering. For the year ended July 31, 2023, Common Shares issued and outstanding under the Shelf Offering remained constant. See Additional Information - Shelf Offering Program for additional information. Initial costs incurred by BLE in connection with its shelf offering are recorded as “Deferred offering costs” in the Statements of Assets and Liabilities. As shares are sold, a portion of the costs attributable to the shares sold will be charged against paid-in-capital. Any remaining deferred charges at the end of the shelf offering period will be charged to expense. Preferred Shares A Trust’s Preferred Shares rank prior to its Common Shares as to the payment of dividends by the Trust and distribution of assets upon dissolution or liquidation of the Trust. The 1940 Act prohibits the declaration of any dividend on Common Shares or the repurchase of Common Shares if the Trust fails to maintain asset coverage of at least 200% of the liquidation preference of the Trust’s outstanding Preferred Shares. In addition, pursuant to the Preferred Shares’ governing instruments, a Trust is restricted from declaring and paying dividends on classes of shares ranking junior to or on parity with its Preferred Shares or repurchasing such shares if the Trust fails to declare and pay dividends on the Preferred Shares, redeem any Preferred Shares required to be redeemed under the Preferred Shares’ governing instruments or comply with the basic maintenance amount requirement of the ratings agencies rating the Preferred Shares. Holders of Preferred Shares have voting rights equal to the voting rights of holders of Common Shares (one vote per share) and vote together with holders of Common Shares (one vote per share) as a single class on certain matters. Holders of Preferred Shares, voting as a separate class, are also entitled to (i) elect two members of the Board, (ii) elect the full Board if dividends on the Preferred Shares are not paid for a period of two years and (iii) a separate class vote to amend the Preferred Share governing documents. In addition, the 1940 Act requires the approval of the holders of a majority of any outstanding Preferred Shares, voting as a separate class, to (a) adopt any plan of reorganization that would adversely affect the Preferred Shares, (b) change a Trust’s sub-classification as a closed-end investment company or change its fundamental investment restrictions or (c) change its business so as to cease to be an investment company. VMTP Shares Each Trust (for purposes of this section, each a “VMTP Trust”) has issued Series W-7 VMTP Shares, $100,000 liquidation preference per share, in one or more privately negotiated offerings to qualified institutional buyers as defined pursuant to Rule 144A under the Securities Act. The VMTP Shares are subject to certain restrictions on transfer, and a VMTP Trust may also be required to register its VMTP Shares for sale under the Securities Act under certain circumstances. As of period end, the VMTP Shares outstanding and assigned long-term ratings were as follows: Trust Name Issue Shares Aggregate Term Moody’s Fitch BYM 12/16/2011 1,372 $ 137,200,000 07/02/24 Aa1 AA BLE 12/16/2011 1,513 151,300,000 07/02/24 Aa1 AA 04/12/2021 1,514 151,400,000 07/02/24 Aa1 AA MVF 12/16/2011 2,438 243,800,000 07/02/24 Aa1 AA Redemption Terms: Subject to certain conditions, VMTP Shares may be redeemed, in whole or in part, at any time at the option of the VMTP Trust. With respect to each VMTP Trust, the redemption price per VMTP Share is equal to the liquidation preference per share plus any outstanding unpaid dividends and applicable redemption premium. If each VMTP Trust redeems the VMTP Shares prior to the term redemption date and the VMTP Shares have long-term ratings above A1/A+ or its equivalent by the ratings agencies then rating the VMTP Shares, then such redemption may be subject to a prescribed redemption premium (up to 1% of the liquidation preference) payable to the holder of the VMTP Shares based on the time remaining until the term redemption date, subject to certain exceptions for redemptions that are required to comply with minimum asset coverage requirements. Dividends: The dividend rate on VMTP Shares is subject to a step-up spread if the VMTP Trust fails to comply with certain provisions, including, among other things, the timely payment of dividends, redemptions or gross-up payments, and complying with certain asset coverage and leverage requirements. For the year ended July 31, 2023, the average annualized dividend rates for the VMTP Shares were as follows: BYM BLE MVF Dividend rates 4.05 % 4.05 % 4.05 % For the year ended July 31, 2023, VMTP Shares issued and outstanding of each VMTP Trust remained constant. Offering Costs: Financial Reporting: as tax-exempt income for tax-reporting purposes. Dividends and amortization of deferred offering costs on VMTP Shares are included in interest expense, fees and amortization of offering costs in the Statements of Operations: Trust Name Dividends Accrued Deferred Offering BYM $ 5,556,795 $ — BLE 12,267,765 — MVF 9,875,855 — | |||||||||||||||||||||||||||||||||||||||
| Security Liquidation Rights [Text Block] | A Trust’s Preferred Shares rank prior to its Common Shares as to the payment of dividends by the Trust and distribution of assets upon dissolution or liquidation of the Trust. | |||||||||||||||||||||||||||||||||||||||
| Outstanding Securities [Table Text Block] | BYM and BLE are authorized to issue an unlimited number of shares, including Preferred Shares, par value $0.001 per share, all of which were initially classified as Common Shares. | |||||||||||||||||||||||||||||||||||||||
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| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Illiquidity Risk: | |||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Market Risk: Municipal securities are subject to the risk that litigation, legislation or other political events, local business or economic conditions, credit rating downgrades, or the bankruptcy of the issuer could have a significant effect on an issuer’s ability to make payments of principal and/or interest or otherwise affect the value of such securities. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to, taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the discontinuance of the tax benefits supporting the project or assets or the inability to collect revenues for the project or from the assets. Municipal securities may be less liquid than taxable bonds, and there may be less publicly available information on the financial condition of municipal security issuers than for issuers of other securities. | |||||||||||||||||||||||||||||||||||||||
| Infectious Illness Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Infectious Illness Risk: | |||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Geographic/Asset Class Risk: The Trusts invest a significant portion of their assets in securities within a single or limited number of market sectors. When a fund concentrates its investments in this manner, it assumes the risk that economic, regulatory, political and social conditions affecting such sectors may have a significant impact on the Trust and could affect the income from, or the value or liquidity of, the Trust’s portfolio. Investment percentages in specific sectors are presented in the Schedules of Investments. Certain Trusts invest a significant portion of their assets in high yield securities. High yield securities that are rated below investment-grade (commonly referred to as “junk bonds”) or are unrated may be deemed speculative, involve greater levels of risk than higher-rated securities of similar maturity and are more likely to default. High yield securities may be issued by less creditworthy issuers, and issuers of high yield securities may be unable to meet their interest or principal payment obligations. High yield securities are subject to extreme price fluctuations, may be less liquid than higher rated fixed-income securities, even under normal economic conditions, and frequently have redemption features. The Trusts invest a significant portion of their assets in fixed-income securities and/or use derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and other fixed-income securities will decrease as interest rates rise and increase as interest rates fall. The Trusts may be subject to a greater risk of rising interest rates due to the period of historically low interest rates that ended in March 2022. The Federal Reserve has recently been raising the federal funds rate as part of its efforts to address inflation. There is a risk that interest rates will continue to rise, which will likely drive down the prices of bonds and other fixed-income securities, and could negatively impact the Trusts’ performance. The Trusts invest a significant portion of their assets in securities of issuers located in the United States. A decrease in imports or exports, changes in trade regulations, inflation and/or an economic recession in the United States may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the United States may also have a significant effect on U.S. markets generally, as well as on the value of certain securities. Governmental agencies project that the United States will continue to maintain elevated public debt levels for the foreseeable future which may constrain future economic growth. Circumstances could arise that could prevent the timely payment of interest or principal on U.S. government debt, such as reaching the legislative “debt ceiling.” Such non-payment would result in substantial negative consequences for the U.S. economy and the global financial system. If U.S. relations with certain countries deteriorate, it could adversely affect issuers that rely on the United States for trade. The United States has also experienced increased internal unrest and discord. If these trends were to continue, they may have an adverse impact on the U.S. economy and the issuers in which the Trusts invest. | |||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Investment and Market Discount Risk: could decrease as a result of its investment activities. At any point in time an investment in the Fund’s common shares may be worth less than the original amount invested, even after taking into account distributions paid by the Fund. During periods in which the Fund may use leverage, the Fund’s investment, market discount and certain other risks will be magnified. | |||||||||||||||||||||||||||||||||||||||
| Debt Securities Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Debt Securities Risk: • Interest Rate Risk — The market value of bonds and other fixed-income securities changes in response to interest rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Fund may be subject to a greater risk of rising interest rates due to the recent period of historically low interest rates. For example, if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being equal, the value of the Fund’s investments would be expected to decreaseby10%. (Duration is a measure of the price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.)The magnitude of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund management. To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities. These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in value when interest rates change. A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could hurt the Fund’s performance. • Credit Risk — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation. • Extension Risk — When interest rates rise, certain obligations will be paid off by the obligor more slowly than anticipated, causing the value of these obligations to fall. • Prepayment Risk — When interest rates fall, certain obligations will be paid off by the obligor more quickly than originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields. | |||||||||||||||||||||||||||||||||||||||
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| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Municipal Securities Risks: • General Obligation Bonds Risks — Timely payments depend on the issuer’s credit quality, ability to raise tax revenues and ability to maintain an adequate tax base. • Revenue Bonds Risks — These payments depend on the money earned by the particular facility or class of facilities, or the amount of revenues derived from another source. • Private Activity Bonds Risks — Municipalities and other public authorities issue private activity bonds to finance development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment. The Fund’s investments may consist of private activity bonds that may subject certain shareholders to an alternative minimum tax. • Moral Obligation Bonds Risks — Moral obligation bonds are generally issued by special purpose public authorities of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral commitment, but not a legal obligation, of the state or municipality. • Municipal Notes Risks — Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the anticipated proceeds, the notes may not be fully repaid and the Fund may lose money. • Municipal Lease Obligations Risks — In a municipal lease obligation, the issuer agrees to make payments when due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease obligation, the lease obligation is secured by the leased property. • Tax-Exempt Status Risk — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds and payments under derivative securities. Neither the Fund nor its investment manager will independently review the bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its shareholders to substantial tax liabilities. | |||||||||||||||||||||||||||||||||||||||
| Taxability Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Taxability Risk: | |||||||||||||||||||||||||||||||||||||||
| Insurance Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Insurance Risk: | |||||||||||||||||||||||||||||||||||||||
| Junk Bonds Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Junk Bonds Risk: | |||||||||||||||||||||||||||||||||||||||
| U S Government Obligations Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | U.S. Government Obligations Risk: | |||||||||||||||||||||||||||||||||||||||
| Leverage Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Leverage Risk: The use of leverage creates an opportunity for increased common share net investment income dividends, but also creates risks for the holders of common shares. The Fund cannot assure you that the use of leverage will result in a higher yield on the common shares. Any leveraging strategy the Fund employs may not be successful. Leverage involves risks and special considerations for common shareholders, including: • the likelihood of greater volatility of net asset value, market price and dividend rate of the common shares than a comparable portfolio without leverage; • the risk that fluctuations in interest rates or dividend rates on any leverage that the Fund must pay will reduce the return to the common shareholders; • the effect of leverage in a declining market, which is likely to cause a greater decline in the net asset value of the common shares than if the Fund were not leveraged, which may result in a greater decline in the market price of the common shares; • leverage may increase operating costs, which may reduce total return. Any decline in the net asset value of the Fund’s investments will be borne entirely by the holders of common shares. Therefore, if the market value of the Fund’s portfolio declines, leverage will result in a greater decrease in net asset value to the holders of common shares than if the Fund were not leveraged. This greater net asset value decrease will also tend to cause a greater decline in the market price for the common shares. | |||||||||||||||||||||||||||||||||||||||
| Tender Option Bonds Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Tender Option Bonds Risk: | |||||||||||||||||||||||||||||||||||||||
| Reverse Repurchase Agreements Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Reverse Repurchase Agreements Risk: | |||||||||||||||||||||||||||||||||||||||
| Illiquid Investments Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Illiquid Investments Risk: 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. Privately issued debt securities are often of below investment grade quality, frequently are unrated and present many of the same risks as investing in below investment grade public debt securities. | |||||||||||||||||||||||||||||||||||||||
| Investment Companies and ETFs Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Investment Companies and ETFs Risk (BLE): The securities of other investment companies and ETFs in which the Fund may invest may be leveraged. As a result, the Fund may be indirectly exposed to leverage through an investment in such securities. An investment in securities of other investment companies and ETFs that use leverage may expose the Fund to higher volatility in the market value of such securities and the possibility that the Fund’s long-term returns on such securities (and, indirectly, the long-term returns of shares of the Fund) will be diminished. As with other investments, investments in other investment companies, including ETFs, are subject to market and selection risk. To the extent the Fund is held by an affiliated fund, the ability of the Fund itself to hold other investment companies may be limited. | |||||||||||||||||||||||||||||||||||||||
| Derivatives Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Derivatives Risk: • Leverage Risk — The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market movements may result in large changes in the value of a derivatives position and can result in losses that greatly exceed the amount originally invested. • Market Risk — Some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally, the Manager may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s derivatives positions to lose value. • Counterparty Risk — Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated exposure to such a counterparty. • Illiquidity Risk — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. • Operational Risk — The use of derivatives includes the risk of potential operational issues, including documentation issues, settlement issues, systems failures, inadequate controls and human error. • Legal Risk — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or enforceability of a contract. • Volatility and Correlation Risk — Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate with the overall securities markets. • Valuation Risk — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to purchase complex instruments or quote prices for them. • Hedging Risk — Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging may result in certain adverse tax consequences. • Tax Risk — Certain aspects of the tax treatment of derivative instruments, including swap agreements and commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund realizes from its investments. | |||||||||||||||||||||||||||||||||||||||
| Risk of Investing in the United States [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Risk of Investing in the United States: | |||||||||||||||||||||||||||||||||||||||
| Market Risk and Selection Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Market Risk and Selection Risk: An outbreak of an infectious coronavirus (COVID-19) that was first detected in December 2019 developed into a global pandemic that has resulted in numerous disruptions in the market and has had significant economic impact leaving general concern and uncertainty. Although vaccines have been developed and approved for use by various governments, the duration of the pandemic and its effects cannot be predicted with certainty. The impact of this coronavirus, and other epidemics and pandemics that may arise in the future, could affect the economies of many nations, individual companies and the market in general ways that cannot necessarily be foreseen at the present time. | |||||||||||||||||||||||||||||||||||||||
| Counterparty Credit Risk [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Counterparty Credit Risk: A derivative contract may suffer a mark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract. With exchange-traded futures, there is less counterparty credit risk to the Trusts since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, a Trust does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Trusts. | |||||||||||||||||||||||||||||||||||||||
| Common Shares [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Lowest Price or Bid | $ 9.96 | $ 10.25 | $ 9.49 | $ 9.43 | $ 10.57 | $ 10.63 | $ 13.65 | $ 14.86 | $ 15.35 | $ 14.78 | $ 15 | $ 14.28 | ||||||||||||||||||||||||||||
| Highest Price or Bid | 10.54 | 11.06 | 11.09 | 11.95 | 11.86 | 13.90 | 15.38 | 16.14 | 16.10 | 15.83 | 16.16 | 15.66 | ||||||||||||||||||||||||||||
| Lowest Price or Bid, NAV | 11.69 | 11.72 | 10.82 | 10.64 | 11.78 | 11.72 | 14.10 | 14.96 | 15.18 | 14.82 | 14.83 | 14.51 | ||||||||||||||||||||||||||||
| Highest Price or Bid, NAV | $ 12.17 | $ 12.38 | $ 12.29 | $ 12.60 | $ 12.78 | $ 14.14 | $ 15.03 | $ 15.18 | $ 15.18 | $ 15.18 | $ 15.46 | $ 14.98 | ||||||||||||||||||||||||||||
| Highest Price or Bid, Premium (Discount) to NAV [Percent] | (13.39%) | (10.66%) | (9.76%) | (5.16%) | (7.20%) | (1.70%) | 2.33% | 6.32% | 6.06% | 5.46% | 4.53% | 6.10% | ||||||||||||||||||||||||||||
| Lowest Price or Bid, Premium (Discount) to NAV [Percent] | 14.80% | 12.54% | (12.29%) | (11.37%) | (10.27%) | (9.30%) | (3.19%) | (0.67%) | 1.12% | (0.67%) | (0.07%) | (1.65%) | ||||||||||||||||||||||||||||
| Share Price | $ 10.45 | $ 10.45 | $ 10.45 | |||||||||||||||||||||||||||||||||||||
| NAV Per Share | $ 12.09 | $ 12.09 | $ 12.09 | |||||||||||||||||||||||||||||||||||||
| Latest Premium (Discount) to NAV [Percent] | (13.56%) | |||||||||||||||||||||||||||||||||||||||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Outstanding Security, Held [Shares] | 48,273,052 | |||||||||||||||||||||||||||||||||||||||
| Preferred Shares [Member] | ||||||||||||||||||||||||||||||||||||||||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Security Title [Text Block] | Preferred Shares | |||||||||||||||||||||||||||||||||||||||
| Security Dividends [Text Block] | A Trust’s Preferred Shares rank prior to its Common Shares as to the payment of dividends by the Trust and distribution of assets upon dissolution or liquidation of the Trust. The 1940 Act prohibits the declaration of any dividend on Common Shares or the repurchase of Common Shares if the Trust fails to maintain asset coverage of at least 200% of the liquidation preference of the Trust’s outstanding Preferred Shares. In addition, pursuant to the Preferred Shares’ governing instruments, a Trust is restricted from declaring and paying dividends on classes of shares ranking junior to or on parity with its Preferred Shares or repurchasing such shares if the Trust fails to declare and pay dividends on the Preferred Shares, redeem any Preferred Shares required to be redeemed under the Preferred Shares’ governing instruments or comply with the basic maintenance amount requirement of the ratings agencies rating the Preferred Shares. | |||||||||||||||||||||||||||||||||||||||
| Security Voting Rights [Text Block] | Holders of Preferred Shares have voting rights equal to the voting rights of holders of Common Shares (one vote per share) and vote together with holders of Common Shares (one vote per share) as a single class on certain matters. Holders of Preferred Shares, voting as a separate class, are also entitled to (i) elect two members of the Board, (ii) elect the full Board if dividends on the Preferred Shares are not paid for a period of two years and (iii) a separate class vote to amend the Preferred Share governing documents. In addition, the 1940 Act requires the approval of the holders of a majority of any outstanding Preferred Shares, voting as a separate class, to (a) adopt any plan of reorganization that would adversely affect the Preferred Shares, (b) change a Trust’s sub-classification as a closed-end investment company or change its fundamental investment restrictions or (c) change its business so as to cease to be an investment company. | |||||||||||||||||||||||||||||||||||||||
| Preferred Stock Restrictions, Arrearage [Text Block] | The 1940 Act prohibits the declaration of any dividend on Common Shares or the repurchase of Common Shares if the Trust fails to maintain asset coverage of at least 200% of the liquidation preference of the Trust’s outstanding Preferred Shares. In addition, pursuant to the Preferred Shares’ governing instruments, a Trust is restricted from declaring and paying dividends on classes of shares ranking junior to or on parity with its Preferred Shares or repurchasing such shares if the Trust fails to declare and pay dividends on the Preferred Shares, redeem any Preferred Shares required to be redeemed under the Preferred Shares’ governing instruments or comply with the basic maintenance amount requirement of the ratings agencies rating the Preferred Shares. | |||||||||||||||||||||||||||||||||||||||
| Outstanding Security, Held [Shares] | 3,027 | |||||||||||||||||||||||||||||||||||||||
| TOBs [Member] | ||||||||||||||||||||||||||||||||||||||||
| Financial Highlights [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Senior Securities Amount | $ 33,812 | $ 113,752 | $ 33,812 | $ 113,752 | $ 33,812 | |||||||||||||||||||||||||||||||||||
| Senior Securities Coverage per Unit | [7] | $ 27,213 | $ 9,073 | $ 27,213 | $ 9,073 | $ 27,213 | ||||||||||||||||||||||||||||||||||
| Preferred Stock Liquidating Preference | [8] | |||||||||||||||||||||||||||||||||||||||
| Senior Securities Average Market Value per Unit | [9] | $ 64,345 | $ 134,008 | |||||||||||||||||||||||||||||||||||||
| VMTP Shares [Member] | ||||||||||||||||||||||||||||||||||||||||
| Financial Highlights [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Senior Securities Amount | $ 302,700 | $ 302,700 | $ 302,700 | $ 151,300 | $ 151,300 | $ 151,300 | $ 151,300 | $ 151,300 | $ 151,300 | $ 151,300 | $ 151,300 | $ 302,700 | $ 302,700 | $ 302,700 | $ 302,700 | |||||||||||||||||||||||||
| Senior Securities Coverage per Unit | $ 273,428 | [10] | $ 247,830 | [10] | $ 343,975 | [11] | $ 330,223 | [11] | $ 335,723 | [11] | $ 326,330 | [11] | $ 335,890 | [11] | $ 350,213 | [11] | $ 336,529 | [11] | $ 339,946 | [11] | $ 306,430 | [11] | $ 273,428 | [10] | $ 247,830 | [10] | $ 343,975 | [11] | $ 273,428 | [10] | ||||||||||
| Preferred Stock Liquidating Preference | [8] | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 | $ 100,000 | $ 100,000 | $ 100,000 | $ 100,000 | ||||||||||||||||||||||||
| Senior Securities Average Market Value per Unit | ||||||||||||||||||||||||||||||||||||||||
| Note [Member] | ||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | ||||||||||||||||||||||||||||||||||||||||
| Investment Objectives and Practices [Text Block] | Investment Objective BlackRock Municipal Income Trust II’s (BLE) (the “Trust”) No assurance can be given that the Trust’s investment objective will be achieved. | |||||||||||||||||||||||||||||||||||||||
| [1]BLE shareholders will pay all offering expenses involved with this offering.[2]Computershare Trust Company, N.A.’s (the “Reinvestment Plan Agent”) fees for the handling of the reinvestment of dividends will be paid by BLE. However, shareholders will pay a $0.02 per share fee incurred in connection with open-market purchases, which will be deducted from the value of the dividend. Shareholders will also be charged a $2.50 sales fee and pay a $0.15 per share fee if direct the Reinvestment Plan Agent to sell the common shares held in a dividend reinvestment account. Per share fees include any applicable brokerage commissions the Reinvestment Plan Agent is required to pay.[3]BLE and the Manager have entered into a fee waiver agreement (the “Fee Waiver Agreement”), pursuant to which the Manager has contractually agreed to waive the management fee with respect to any portion of BLE’s assets attributable to investments in any equity and fixed-income mutual funds and exchange-traded funds managed by the Manager or its affiliates that have a contractual management fee, through June 30, 2025. In addition, pursuant to the Fee Waiver Agreement, the Manager has contractually agreed to waive its management fees by the amount of investment advisory fees BLE pays to the Manager indirectly through its investment in money market funds managed by the Manager or its affiliates, through June 30, 2025. The Fee Waiver Agreement may be terminated at any time, without the payment of any penalty, only by BLE (upon the vote of a majority of the Trustees who are not “interested persons” (as defined in the Investment Company Act) of the Trust or a majority of the outstanding voting securities of BLE), upon 90 days’ written notice by BLE to the Manager.[4]BLE currently pays the Manager a monthly fee at an annual contractual investment management fee rate of 0.55% of its average weekly managed assets. For purposes of calculating these fees, “managed assets” means the total assets of BLE (including any assets attributable to money borrowed for investment purposes) minus the sum of its accrued liabilities (other than money borrowed for investment purposes).[5]The total annual expenses do not correlate to the ratios to average net assets shown in BLE’s Financial Highlights for the year ended July 31, 2023, which do not include acquired fund fees and expenses.[6]Assumes the use of leverage in the form of tender option bond transactions and preferred shares representing 37% of Managed Assets at an annual cost of leverage to BLE of 3.88%, which is based on current market conditions. The actual amount of interest expense borne by BLE will vary over time in accordance with the level of BLE’s use of tender option bond transactions and variations in market interest rates, as well as preferred shares transactions and changes to agreement terms with counterparties. Interest expense is required to be treated as an expense of BLE for accounting purposes.BLE uses leverage to seek to enhance its returns to common shareholders. This leverage generally takes two forms: the issuance of VMTP Shares and investment in TOBs. Both forms of leverage benefit common shareholders if the cost of the leverage is lower than the returns earned by BLE when it invests the proceeds from the leverage. In order to help you better understand the costs associated with BLE’s leverage strategy, the total annual Trust operating expenses after fee waivers (excluding interest expense) are 0.97%.[7]Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares and TOBs) from the Trust’s total assets and dividing this by the amount of TOBs, and by multiplying the results by 1,000.[8]Represents the amount to which a holder of preferred shares would be entitled upon the liquidation of VMTP Shares in preference to common shareholders, expressed as a dollar amount per preferred share. VMTP Shares are considered debt of the issuer; therefore, the liquidation preference approximates fair value.[9]Represents weighted average daily market value of TOBs.[10]Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares and TOBs) from the Trust’s total assets and dividing this by the sum of the amount of TOBs and liquidation value of the VMTP Shares, and by multiplying the results by 100,000. Effective July 18, 2022, TOB Trust Certificates are treated as senior securities pursuant to Rule 18f-4 of the 1940 Act.[11]Calculated by subtracting the Trust’s total liabilities (not including VMTP Shares) from the Trust’s total assets and dividing this by the liquidation value of the VMTP Shares, and by multiplying the results by 100,000. | ||||||||||||||||||||||||||||||||||||||||
