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N-2 - USD ($) |  |  | 3 Months Ended
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Sep. 30, 2022 | Sep. 22, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2021 | Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Central Index Key |  | 0000832327 |  |  |  |  |  |  |  |  |  |  |
Amendment Flag |  | false |  |  |  |  |  |  |  |  |  |  |
Securities Act File Number |  | 333-262743 |  |  |  |  |  |  |  |  |  |  |
Investment Company Act File Number |  | 811-05542 |  |  |  |  |  |  |  |  |  |  |
Document Type |  | N-2 |  |  |  |  |  |  |  |  |  |  |
Document Registration Statement |  | true |  |  |  |  |  |  |  |  |  |  |
Pre-Effective Amendment |  | false |  |  |  |  |  |  |  |  |  |  |
Post-Effective Amendment |  | true |  |  |  |  |  |  |  |  |  |  |
Post-Effective Amendment Number |  | 2 |  |  |  |  |  |  |  |  |  |  |
Investment Company Act Registration |  | true |  |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment |  | true |  |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment Number |  | 11 |  |  |  |  |  |  |  |  |  |  |
Entity Registrant Name |  | BlackRock Income Trust, Inc. |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | 100 Bellevue Parkway |  |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | Wilmington |  |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | DE |  |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 19809 |  |  |  |  |  |  |  |  |  |  |
City Area Code |  | 800 |  |  |  |  |  |  |  |  |  |  |
Local Phone Number |  | 882-0052 |  |  |  |  |  |  |  |  |  |  |
Approximate Date of Commencement of Proposed Sale to Public |  | From time to time after the effective date of this Registration Statement. |  |  |  |  |  |  |  |  |  |  |
Dividend or Interest Reinvestment Plan Only |  | false |  |  |  |  |  |  |  |  |  |  |
Delayed or Continuous Offering |  | true |  |  |  |  |  |  |  |  |  |  |
Primary Shelf [Flag] |  | true |  |  |  |  |  |  |  |  |  |  |
Effective Upon Filing, 462(e) |  | false |  |  |  |  |  |  |  |  |  |  |
Additional Securities Effective, 413(b) |  | false |  |  |  |  |  |  |  |  |  |  |
Effective when Declared, Section 8(c) |  | true |  |  |  |  |  |  |  |  |  |  |
New Effective Date for Previous Filing |  | false |  |  |  |  |  |  |  |  |  |  |
Additional Securities. 462(b) |  | false |  |  |  |  |  |  |  |  |  |  |
No Substantive Changes, 462(c) |  | false |  |  |  |  |  |  |  |  |  |  |
Exhibits Only, 462(d) |  | false |  |  |  |  |  |  |  |  |  |  |
Registered Closed-End Fund [Flag] |  | true |  |  |  |  |  |  |  |  |  |  |
Business Development Company [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |
Interval Fund [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |
Primary Shelf Qualified [Flag] |  | true |  |  |  |  |  |  |  |  |  |  |
Entity Well-known Seasoned Issuer |  | No |  |  |  |  |  |  |  |  |  |  |
Entity Emerging Growth Company |  | false |  |  |  |  |  |  |  |  |  |  |
New CEF or BDC Registrant [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |
Fee Table [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Shareholder Transaction Expenses [Table Text Block] |  |
Shareholder Transaction Expenses |  |  |  |
Sales load paid by you (as a percentage of offering price) (1) |  |  | 1.00 | %
Offering expenses borne by the Fund (as a percentage of offering price) (1) |  |  | 0.05 | %
Dividend reinvestment plan fees |  | $ | 0.02 per share for open- market purchases of common shares | (2)
Dividend reinvestment plan sale transaction fee |  | $ | 2.50 | (2)
(1) | If the common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load and the estimated offering expenses . Fund shareholders will pay all offering expenses involved with an offering.
(2) | The Reinvestment Plan Agent’s (as defined below under “Dividend Reinvestment Plan”) fees for the handling of the reinvestment of dividends will be paid by the Fund. However, you 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. You will also be charged a $2.50 sales fee and pay a $0.15 per share fee if you direct the Reinvestment Plan Agent to sell your 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] | 1.00% |  |  |  |  |  |  |  |  |  |  |
Dividend Reinvestment and Cash Purchase Fees | [2] | $ 0.02 |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expenses [Percent] | [1] | 0.05% |  |  |  |  |  |  |  |  |  |  |
Annual Expenses [Table Text Block] |  |
Estimated Annual Expenses (as a percentage of net assets attributable to common shares) |  |  |  |
Management fees (3)(4) |  |  | 0.65 | %
Other Expenses |  |  | 0.29 | %
Miscellaneous Other Expenses |  |  | 0.25 | %
Interest Expense (5) |  |  | 0.04 | %
Total Annual Fund Operating Expenses |  |  | 0.94 | %
Fee Waivers and/or Expense Reimbursements (4) |  |  | — | %
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (4) |  |  | 0.94 | %
(3) | The Fund currently pays the Advisor a monthly fee at an annual contractual investment management fee rate of 0.65% of the average weekly value of the Fund’s Net Assets. “Net Assets” means the total assets of the Fund minus the sum of its accrued liabilities (including the aggregate indebtedness constituting financial leverage).
(4) | The Fund and the Advisor have entered into a fee waiver agreement (the “Fee Waiver Agreement”), pursuant to which the Advisor has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets attributable to investments in any equity and fixed-income mutual funds and ETFs managed by the Advisor or its affiliates that have a contractual management fee, through June 30, 2024. In addition, pursuant to the Fee Waiver Agreement, the Advisor has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to the Advisor indirectly through its investment in money market funds managed by the Advisor or its affiliates, through June 30, 2024. The Fee Waiver Agreement may be terminated at any time, without the payment of any penalty, only by the Fund (upon the vote of a majority of the Directors who are not “interested persons” (as defined in the Investment Company Act) of the Fund (the “Independent Directors”) or a majority of the outstanding voting securities of the Fund), upon 90 days’ written notice by the Fund to the Advisor.
(5) | Assumes the use of leverage in the form of reverse repurchase agreements representing 32.6% of Managed Assets at an annual interest expense to the Fund of 0.12% which is based on current market conditions. The actual amount of interest expense borne by the Fund will vary over time in accordance with the level of the Fund’s use of reverse repurchase agreements and variations in market interest rates. Interest expense is required to be treated as an expense of the Fund for accounting purposes.
Management Fees [Percent] | [3],[4] | 0.65% |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expense 1 [Percent] |  | 0.25% |  |  |  |  |  |  |  |  |  |  |
Other Annual Expense 2 [Percent] | [5] | 0.04% |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Percent] |  | 0.29% |  |  |  |  |  |  |  |  |  |  |
Total Annual Expenses [Percent] |  | 0.94% |  |  |  |  |  |  |  |  |  |  |
Waivers and Reimbursements of Fees [Percent] | [3] | 0.00% |  |  |  |  |  |  |  |  |  |  |
Net Expense over Assets [Percent] | [3] | 0.94% |  |  |  |  |  |  |  |  |  |  |
Expense Example [Table Text Block] |  | The following example illustrates the expenses (including the sales load of $10.00 and offering costs of $0.57) that you would pay on a $1,000 investment in common shares, assuming (i) total net annual expenses of 0.94% of net assets attributable to common shares, and (ii) a 5% annual return:
|  | One Year |  |  | Three Years |  |  | Five Years |  |  | Ten Years |
Total expenses incurred |  | $ | 20 |  |  | $ | 40 |  |  | $ | 62 |  |  | $ | 125 |
Expense Example, Year 01 |  | $ 20 |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 3 |  | 40 |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 5 |  | 62 |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 10 |  | $ 125 |  |  |  |  |  |  |  |  |  |  |
Basis of Transaction Fees, Note [Text Block] | [1] | as a percentage of offering price |  |  |  |  |  |  |  |  |  |  |
Other Expenses, Note [Text Block] |  | The example should not be considered a representation of future expenses. The example assumes that the estimated “Other expenses” set forth in the Estimated Annual Expenses table are accurate and that all dividends and distributions are reinvested at NAV. 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. |  |  |  |  |  |  |  |  |  |  |
Management Fee not based on Net Assets, Note [Text Block] |  | If the common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load and the estimated offering expenses . Fund shareholders will pay all offering expenses involved with an offering. |  |  |  |  |  |  |  |  |  |  |
Acquired Fund Total Annual Expenses, Note [Text Block] |  | The Fund and the Advisor have entered into a fee waiver agreement (the “Fee Waiver Agreement”), pursuant to which the Advisor has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets attributable to investments in any equity and fixed-income mutual funds and ETFs managed by the Advisor or its affiliates that have a contractual management fee, through June 30, 2024. In addition, pursuant to the Fee Waiver Agreement, the Advisor has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to the Advisor indirectly through its investment in money market funds managed by the Advisor or its affiliates, through June 30, 2024. The Fee Waiver Agreement may be terminated at any time, without the payment of any penalty, only by the Fund (upon the vote of a majority of the Directors who are not “interested persons” (as defined in the Investment Company Act) of the Fund (the “Independent Directors”) or a majority of the outstanding voting securities of the Fund), upon 90 days’ written notice by the Fund to the Advisor. |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Objectives and Practices [Text Block] |  | Investment Objective and Policies Please refer to the section of the Fund’s most recent annual report on Form N-CSR entitled “Investment Objectives, Policies and Risks—Investment Objectives and Policies—BlackRock Income Trust, Inc.”, which is incorporated by reference herein, for a discussion of the Fund’s investment objective and policies. |  |  |  |  |  |  |  |  |  |  |
Risk Factors [Table Text Block] |  | RISKS The NAV and market price of, and dividends paid on, the common shares will fluctuate with and be affected by, among other things, the risks of investing in the Fund. General Risks Please refer to the section of the Fund’s most recent annual report on Form N-CSR entitled “Investment Objectives, Policies and Risks—Risk Factors”, which is incorporated by reference herein, for a discussion of the general risks of investing in the Fund. Other Risks When-Issued, Forward Commitment and Delayed Delivery Transactions Risk The Fund may purchase securities on a when-issued basis (including on a forward commitment or “TBA” (to be announced) basis) and may purchase or sell securities for delayed delivery. When-issued and delayed delivery transactions occur when securities are purchased or sold by the Fund with payment and delivery taking place in the future to secure an advantageous yield or price. Securities purchased on a when-issued or delayed delivery basis may expose the Fund to counterparty risk of default as well as the risk that securities may experience fluctuations in value prior to their actual delivery. The Fund will not accrue income with respect to a when-issued or delayed delivery security prior to its stated delivery date. Purchasing securities on a when-issued or delayed delivery basis can involve the additional risk that the price or yield available in the market when the delivery takes place may not be as favorable as that obtained in the transaction itself. Collateralized Debt Obligations Risk In addition to the typical risks associated with fixed-income securities and asset-backed securities, collateralized debt obligations (“CDOs”), including collateralized loan obligations, carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the risk that the collateral may default or decline in value or be downgraded, if rated by a nationally recognized statistical rating organization; (iii) the Fund may invest in tranches of CDOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; (v) the investment return achieved by the Fund could be significantly different than those predicted by financial models; (vi) the lack of a readily available secondary market for CDOs; (vii) the risk of forced “fire sale” liquidation due to technical defaults such as coverage test failures; and (viii) the CDO’s manager may perform poorly. Dollar Rolls Risk Dollar rolls involve the risk that the market value of the securities that the Fund is committed to buy may decline below the price of the securities the Fund has sold. These transactions may involve leverage. Short Sales Risk Because making short sales in securities that it does not own exposes the Fund to the risks associated with those securities, such short sales involve speculative exposure risk. The Fund will incur a loss as a result of a short sale if the price of the security increases between the date of the short sale and the date on which the Fund replaces the security sold short. Investment Companies and ETFs Risk Subject to the limitations set forth in the 1940 Act and the rules thereunder, the Fund may acquire shares in other investment companies and in ETFs, some of which may be affiliated investment companies. The market value of the shares of other investment companies and ETFs may differ from their net asset value. As an investor in investment companies and ETFs, the Fund would bear its ratable share of that entity’s expenses, including its investment advisory and administration fees, while continuing to pay its own advisory and administration fees and other expenses (to the extent not offset by the Advisor through waivers). As a result, shareholders will be absorbing duplicate levels of fees with respect to investments in other investment companies and ETFs (to the extent not offset by the Advisor through waivers). 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. Securities Lending Risk The Fund may lend securities to financial institutions. Securities lending involves exposure to certain risks, including operational risk (i.e., the risk of losses resulting from problems in the settlement and accounting process), “gap” risk (i.e., the risk of a mismatch between the return on cash collateral reinvestments and the fees the Fund has agreed to pay a borrower), foreign exchange risk (i.e., the risk of a shortfall at default when a cash collateral investment is denominated in a currency other than the currency of the assets being loaned due to movements in foreign exchange rates), and credit, legal, counterparty and market risks. If a securities lending counterparty were to default, the Fund would be subject to the risk of a possible delay in receiving collateral or in recovering the loaned securities, or to a possible loss of rights in the collateral. In the event a borrower does not return the Fund’s securities as agreed, the Fund may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated, plus the transaction costs incurred in purchasing replacement securities. This event could trigger adverse tax consequences for the Fund. The Fund could lose money if its short-term investment of the collateral declines in value over the period of the loan. Substitute payments for dividends received by the Fund for securities loaned out by the Fund will generally not be considered qualified dividend income. The securities lending agent will take the tax effects on shareholders of this difference into account in connection with the Fund’s securities lending program. Substitute payments received on tax-exempt securities loaned out will generally not be tax-exempt income. Inflation Risk Inflation risk is the risk that the value of assets or income from investment will be worth less in the future, as inflation decreases the value of money. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy. As inflation increases, the real value of the common shares and distributions on those shares can decline. In addition, during any periods of rising inflation, interest rates on any borrowings by the Trust would likely increase, which would tend to further reduce returns to the holders of common shares. Deflation Risk Deflation risk is the risk that prices throughout the economy decline over time, which may have an adverse effect on the market valuation of companies, their assets and their revenues. In addition, deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund’s portfolio. Swaps Risk Swaps are a type of derivative. Swap agreements involve the risk that the party with which the Fund has entered into the swap will default on its obligation to pay the Fund and the risk that the Fund will not be able to meet its obligations to pay the other party to the agreement. In order to seek to hedge the value of the Fund’s portfolio, to hedge against increases in the Fund’s cost associated with interest payments on any outstanding borrowings or to seek to increase the Fund’s return, the Fund may enter into swaps, including interest rate swap, total return swap (sometimes referred to as a “contract for difference”) and/or credit default swap transactions. In interest rate swap transactions, there is a risk that yields will move in the direction opposite of the direction anticipated by the Fund, which would cause the Fund to make payments to its counterparty in the transaction that could adversely affect Fund performance. In addition to the risks applicable to swaps generally (including counterparty risk, high volatility, illiquidity risk and credit risk), credit default swap transactions involve special risks because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). Historically, swap transactions have been individually negotiated non-standardized transactions entered into in OTC markets and have not been subject to the same type of government regulation as exchange-traded instruments. However, since the global financial crisis, the OTC derivatives markets have become subject to comprehensive statutes and regulations. In particular, in the United States, the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the “Dodd-Frank Act”), signed into law by President Obama on July 21, 2010, requires that certain derivatives with U.S. persons must be executed on a regulated market and a substantial portion of OTC derivatives must be submitted for clearing to regulated clearinghouses. As a result, swap transactions entered into by the Fund may become subject to various requirements applicable to swaps under the Dodd-Frank Act, including clearing, exchange-execution, reporting and recordkeeping requirements, which may make it more difficult and costly for the Fund to enter into swap transactions and may also render certain strategies in which the Fund might otherwise engage impossible or so costly that they will no longer be economical to implement. Furthermore, the number of counterparties that may be willing to enter into swap transactions with the Fund may also be limited if the swap transactions with the Fund are subject to the swap regulation under the Dodd-Frank Act. Risk Associated with Recent Market Events While interest rates have been historically low in recent years in the United States and abroad, inflation rates have recently risen significantly and the Federal Reserve and other central banks have recently begun raising interest rates to address inflation which, among other factors, has led to markets to experiencing high volatility. A significant increase in interest rates may cause a further decline in the market for equity securities and could lead to a recession. Further, regulators have expressed concern that rate increases may contribute to price volatility. The impact of inflation and the recent actions of the Federal Reserve have led to market volatility and may negatively affect the value of debt instruments held by the Fund and result in a negative impact on the Fund’s performance. See “Risks—Inflation Risk.” In addition, the current contentious domestic political environment, as well as political and diplomatic events in the United States and abroad, such as presidential elections in the United States or the U.S. government’s inability at times to agree on a long-term budget and deficit reduction plan, has in the past resulted, and may in the future result, in adverse consequences (including a government shutdown) to the U.S. regulatory landscape, the general market environment and/or investment sentiment, which could negatively impact the Fund’s investments and operations. Such adverse consequences may affect investor and/or consumer confidence and may adversely impact financial markets and the broader economy, potentially to a significant degree. In recent years, some countries, including the United States, have adopted and/or are considering the adoption of more protectionist trade policies. A rise in protectionist trade policies, and the possibility of changes to some international trade agreements, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, geopolitical and other risks, including environmental and public health, may add to instability in world economies and markets generally. Economies and financial markets throughout the world are becoming increasingly interconnected. As a result, whether or not the Fund invests in securities of issuers located in or with significant exposure to countries experiencing economic, political and/or financial difficulties, the value and liquidity of the Fund’s investments may be negatively affected by such events. 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. LIBOR Risk The Fund may be exposed to financial instruments that are tied to LIBOR to determine payment obligations, financing terms, hedging strategies or investment value. The Fund’s investments may pay interest at floating rates based on LIBOR or may be subject to interest caps or floors based on LIBOR. The Fund may also obtain financing at floating rates based on LIBOR. Derivative instruments utilized by the Fund may also reference LIBOR. The United Kingdom’s Financial Conduct Authority announced a phase out of LIBOR such that after June 30, 2023, the overnight, 1-month, 3-month, 6-month and 12-month U.S. dollar LIBOR settings will cease to be published or will no longer be representative. All other LIBOR settings and certain other interbank offered rates, such as the Euro Overnight Index Average (“EONIA”), ceased to be published or representative after December 31, 2021. The Fund may have investments linked to other interbank offered rates that may also cease to be published in the future. Various financial industry groups have been planning for the transition away from LIBOR, but there remain challenges to converting certain securities and transactions to a new reference rate (e.g., the Secured Overnight Financing Rate (“SOFR”), which is intended to replace the U.S. dollar LIBOR). Neither the effect of the LIBOR transition process nor its ultimate success can yet be known. The transition process might lead to increased volatility and illiquidity in markets for, and reduce the effectiveness of new hedges placed against, instruments whose terms currently include LIBOR. While some existing LIBOR-based instruments may contemplate a scenario where LIBOR is no longer available by providing for an alternative rate-setting methodology, there may be significant uncertainty regarding the effectiveness of any such alternative methodologies to replicate LIBOR. Not all existing LIBOR-based instruments may have alternative rate-setting provisions and there remains uncertainty regarding the willingness and ability of issuers to add alternative rate-setting provisions in certain existing instruments. Global regulators have advised market participants to cease entering into new contracts using LIBOR as a reference rate, and it is possible that investments in LIBOR-based instruments could invite regulatory scrutiny. In addition, a liquid market for newly issued instruments that use a reference rate other than LIBOR still may be developing. There may also be challenges for the Fund to enter into hedging transactions against such newly issued instruments until a market for such hedging transactions develops. All of the aforementioned may adversely affect the Fund’s performance or NAV. Market Disruption and Geopolitical Risk The occurrence of events similar to those in recent years, such as the aftermath of the war in Iraq, instability in Afghanistan, Pakistan, Egypt, Libya, Syria, Russia, Ukraine and the Middle East, new and ongoing epidemics and pandemics of infectious diseases and other global health events, natural/environmental disasters, terrorist attacks in the United States and around the world, social and political discord, debt crises (such as the Greek crisis), sovereign debt downgrades, the Russian invasion of Ukraine, increasingly strained relations between the United States and a number of foreign countries, including historical adversaries, such as North Korea, Iran, China and Russia, and the international community generally, new and continued political unrest in various countries, such as Venezuela and Spain, the exit or potential exit of one or more countries from the EU or the EMU, and continued changes in the balance of political power among and within the branches of the U.S. government, among others, may result in market volatility, may have long term effects on the U.S. and worldwide financial markets, and may cause further economic uncertainties in the United States and worldwide. Russia launched a large-scale invasion of Ukraine on February 24, 2022. The extent and duration of the military action, resulting sanctions and resulting future market disruptions, including declines in its stock markets and the value of the ruble against the U.S. dollar, in the region are impossible to predict, but could be significant. Any such disruptions caused by Russian military action or other actions (including cyberattacks and espionage) or resulting actual and threatened responses to such activity, including purchasing and financing restrictions, boycotts or changes in consumer or purchaser preferences, sanctions, tariffs or cyberattacks on the Russian government, Russian companies or Russian individuals, including politicians, could have a severe adverse effect on Russia and the European region, including significant negative impacts on the Russian economy, the European economy and the markets for certain securities and commodities, such as oil and natural gas, and may likely have collateral impacts on such sectors globally as well as other sectors. How long such military action and related events will last cannot be predicted. China and the United States have each imposed tariffs on the other country’s products. These actions may cause 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. On January 31, 2020, the United Kingdom (“UK”) officially withdrew from the EU (commonly known as “Brexit”). The UK and EU reached a preliminary trade agreement, which became effective on January 1, 2021, regarding the terms of their future trading relationship relating principally to the trading of goods; however, negotiations are ongoing for matters not covered by the agreement, such as the trade of financial services. Due to uncertainty of the current political environment, it is not possible to foresee the form or nature of the future trading relationship between the UK and the EU. The longer term economic, legal, political and social framework to be put in place between the UK and the EU remains unclear and the ongoing political and economic uncertainty and periods of exacerbated volatility in both the UK and in wider European markets may continue for some time. In particular, Brexit may lead to a call for similar referendums in other European jurisdictions which may cause increased economic volatility in the European and global markets and may destabilize some or all of the other EU member countries. This uncertainty may have an adverse effect on the economy generally and on the ability of the Fund and its investments to execute their respective strategies, to receive attractive returns and/or to exit certain investments at an advantageous time or price. In particular, currency volatility may mean that the returns of the Fund and its investments are adversely affected by market movements and may make it more difficult, or more expensive, if the Fund elects to execute currency hedges. Potential decline in the value of the British Pound and/or the Euro against other currencies, along with the potential downgrading of the UK’s sovereign credit rating, may also have an impact on the performance of portfolio companies or investments located in the UK or Europe. In light of the above, no definitive assessment can currently be made regarding the impact that Brexit will have on the Fund, its investments or its organization more generally. Cybersecurity incidents affecting particular companies or industries may adversely affect the economies of particular countries, regions or parts of the world in which the Fund invests. The occurrence of any of these above events could have a significant adverse impact on the value and risk profile of the Fund’s portfolio. The Fund does not know how long the securities markets may be affected by similar events and cannot predict the effects of similar events in the future on the U.S. economy and securities markets. There can be no assurance that similar events and other market disruptions will not have other material and adverse implications. Regulation and Government Intervention Risk Federal, state, and other governments, their regulatory agencies or self-regulatory organizations may take actions that affect the regulation of the issuers in which the Fund invests in ways that are unforeseeable. Legislation or regulation may also change the way in which the Fund is regulated. Such legislation or regulation could limit or preclude the Fund’s ability to achieve its investment objective. In light of popular, political and judicial focus on finance related consumer protection. Financial institution practices are also subject to greater scrutiny and criticism generally. In the case of transactions between financial institutions and the general public, there may be a greater tendency toward strict interpretation of terms and legal rights in favor of the consuming public, particularly where there is a real or perceived disparity in risk allocation and/or where consumers are perceived as not having had an opportunity to exercise informed consent to the transaction. In the event of conflicting interests between retail investors holding common shares of a closed-end investment company such as the Fund and a large financial institution, a court may similarly seek to strictly interpret terms and legal rights in favor of retail investors. The Fund may be affected by governmental action in ways that are not foreseeable, and there is a possibility that such actions could have a significant adverse effect on the Fund and its ability to achieve its investment objective. Investment Company Act Regulations The Fund is a registered closed-end management investment company and as such is subject to regulations under the Investment Company Act. Generally speaking, any contract or provision thereof that is made, or where performance involves a violation of the Investment Company Act or any rule or regulation thereunder is unenforceable by either party unless a court finds otherwise. Regulation as a “Commodity Pool” The CFTC subjects advisers to registered investment companies to regulation by the CFTC if a fund that is advised by the investment adviser either (i) invests, directly or indirectly, more than a prescribed level of its liquidation value in CFTC-regulated futures, options and swaps (“CFTC Derivatives”), or (ii) markets itself as providing investment exposure to such instruments. To the extent the Fund uses CFTC Derivatives, it intends to do so below such prescribed levels and will not market itself as a “commodity pool” or a vehicle for trading such instruments. Accordingly, the Advisor has claimed an exclusion from the definition of the term “commodity pool operator” under the Commodity Exchange Act (“CEA”) pursuant to Rule 4.5 under the CEA. The Advisor is not, therefore, subject to registration or regulation as a “commodity pool operator” under the CEA in respect of the Fund. Failures of Futures Commission Merchants and Clearing Organizations Risk The Fund is required to deposit funds to margin open positions in cleared derivative instruments (both futures and swaps) with a clearing broker registered as a “futures commission merchant” (“FCM”). The CEA requires an FCM to segregate all funds received from customers with respect to any orders for the purchase or sale of U.S. domestic futures contracts and cleared swaps from the FCM’s proprietary assets. Similarly, the CEA requires each FCM to hold in a separate secure account all funds received from customers with respect to any orders for the purchase or sale of foreign futures contracts and segregate any such funds from the funds received with respect to domestic futures contracts. However, all funds and other property received by an FCM from its customers are held by an FCM on a commingled basis in an omnibus account and amounts in excess of assets posted to the clearing organization may be invested by an FCM in certain instruments permitted under the applicable regulation. There is a risk that assets deposited by the Fund with any FCM as margin for futures contracts or commodity options may, in certain circumstances, be used to satisfy losses of other clients of the Fund’s FCM. In addition, the assets of the Fund posted as margin against both swaps and futures contracts may not be fully protected in the event of the FCM’s bankruptcy. Legal, Tax and Regulatory Risks Legal, tax and regulatory changes could occur that may have material adverse effects on the Fund. To qualify for the favorable U.S. federal income tax treatment generally accorded to RICs, the Fund must, among other things, derive in each taxable year at least 90% of (i) its net tax-exempt interest income, if any, and (ii) its gross income from certain prescribed sources and distribute for each taxable year at least 90% of its “investment company taxable income” (generally, ordinary income plus the excess, if any, of net short-term capital gain over net long-term capital loss). If for any taxable year the Fund does not qualify as a RIC, all of its taxable income for that year (including its net capital gain) would be subject to tax at regular corporate rates without any deduction for distributions to shareholders, and such distributions would be taxable as ordinary dividends to the extent of the Fund’s current and accumulated earnings and profits. The Biden presidential administration has called for significant changes to U.S. fiscal, tax, trade, healthcare, immigration, foreign, and government regulatory policy. In this regard, there is significant uncertainty with respect to legislation, regulation and government policy at the federal level, as well as the state and local levels. Recent events have created a climate of heightened uncertainty and introduced new and difficult-to-quantify macroeconomic and political risks with potentially far-reaching implications. There has been a corresponding meaningful increase in the uncertainty surrounding interest rates, inflation, foreign exchange rates, trade volumes and fiscal and monetary policy. To the extent the U.S. Congress or the current presidential administration implements changes to U.S. policy, those changes may impact, among other things, the U.S. and global economy, international trade and relations, unemployment, immigration, corporate taxes, healthcare, the U.S. regulatory environment, inflation and other areas. Although the Fund cannot predict the impact, if any, of these changes to the Fund’s business, they could adversely affect the Fund’s business, financial condition, operating results and cash flows. Until the Fund knows what policy changes are made and how those changes impact the Fund’s business and the business of the Fund’s competitors over the long term, the Fund will not know if, overall, the Fund will benefit from them or be negatively affected by them. The rules dealing with U.S. federal income taxation are constantly under review by persons involved in the legislative process and by the Internal Revenue Service and the U.S. Treasury Department. Revisions in U.S. federal tax laws and interpretations of these laws could adversely affect the tax consequences of your investment . Potential Conflicts of Interest of the Advisor, Sub-Advisor and Others The investment activities of BlackRock, Inc. (“BlackRock”), the ultimate parent company of the Advisors, and its affiliates (including BlackRock and its subsidiaries (collectively, the “Affiliates”))in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BlackRock and its Affiliates provide investment management services to other funds and discretionary managed accounts that may follow investment programs similar to that of the Fund. Subject to the requirements of the Investment Company Act, BlackRock and its Affiliates intend to engage in such activities and may receive compensation from third parties for their services. None of BlackRock or its Affiliates are under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, BlackRock and its Affiliates may compete with the Fund for appropriate investment opportunities. The results of the Fund’s investment activities, therefore, may differ from those of an Affiliate or another account managed by BlackRock or an Affiliate, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates and other accounts achieve profits on their trading for proprietary or other accounts. BlackRock has adopted policies and procedures designed to address potential conflicts of interest. For additional information about potential conflicts of interest and the way in which BlackRock addresses such conflicts, please see “Conflicts of Interest” and “Management of the Fund—Portfolio Management—Potential Material Conflicts of Interest” in the SAI. Defensive Investing Risk For defensive purposes, the Fund may allocate assets into cash or short-term fixed-income securities without limitation. In doing so, the Fund may succeed in avoiding losses but may otherwise fail to achieve its investment objective. Further, the value of short-term fixed-income securities may be affected by changing interest rates and by changes in credit ratings of the investments. If the Fund holds cash uninvested it will be subject to the credit risk of the depository institution holding the cash. Decision-Making Authority Risk Investors have no authority to make decisions or to exercise business discretion on behalf of the Fund, except as set forth in the Fund’s governing documents. The authority for all such decisions is generally delegated to the Board, which in turn, has delegated the day-to-day management of the Fund’s investment activities to the Advisors, subject to oversight by the Board. Management Risk The Fund is subject to management risk because it is an actively managed investment portfolio. The Advisors and the individual portfolio managers will apply investment techniques and risk analyses in making investment decisions for the Fund, but there can be no guarantee that these will produce the desired results. The Fund may be subject to a relatively high level of management risk because the Fund may invest in derivative instruments, which may be highly specialized instruments that require investment techniques and risk analyses different from those associated with equities and bonds. Valuation Risk The Fund is subject to valuation risk, which is the risk that one or more of the securities in which the Fund invests are valued at prices that the Fund is unable to obtain upon sale due to factors such as incomplete data, market instability or human error. The Advisor may use an independent pricing service or prices provided by dealers to value securities at their market value. Because the secondary markets for certain investments may be limited, such instruments may be difficult to value. See “Net Asset Value.” When market quotations are not available, the Advisor may price such investments pursuant to a number of methodologies, such as computer-based analytical modeling or individual security evaluations. These methodologies generate approximations of market values, and there may be significant professional disagreement about the best methodology for a particular type of financial instrument or different methodologies that might be used under different circumstances. In the absence of an actual market transaction, reliance on such methodologies is essential, but may introduce significant variances in the ultimate valuation of the Fund’s investments. Technological issues and/or errors by pricing services or other third-party service providers may also impact the Fund’s ability to value its investments and the calculation of the Fund’s NAV. When market quotations are not readily available or are believed by the Advisor to be unreliable, the Advisor will fair value the Fund’s investments in accordance with its policies and procedures. Fair value represents a good faith approximation of the value of an asset or liability. The fair value of an asset or liability held by the Fund is the amount the Fund might reasonably expect to receive from the current sale of that asset or the cost to extinguish that liability in an arm’s-length transaction. Fair value pricing may require determinations that are inherently subjective and inexact about the value of a security or other asset. As a result, there can be no assurance that fair value priced assets will not result in future adjustments to the prices of securities or other assets, or that fair value pricing will reflect a price that the Fund is able to obtain upon sale, and it is possible that the fair value determined for a security or other asset will be materially different from quoted or published prices, from the prices used by others for the same security or other asset and/or from the value that actually could be or is realized upon the sale of that security or other asset. For example, the Fund’s NAV could be adversely affected if the Fund’s determinations regarding the fair value of the Fund’s investments were materially higher than the values that the Fund ultimately realizes upon the disposal of such investments. Where market quotations are not readily available, valuation may require more research than for more liquid investments. In addition, elements of judgment may play a greater role in valuation in such cases than for investments with a more active secondary market because there is less reliable objective data available. Because of overall size, duration and maturities of positions held by the Fund, the value at which its investments can be liquidated may differ, sometimes significantly, from the interim valuations obtained by the Fund. In addition, the timing of liquidations may also affect the values obtained on liquidation. Securities held by the Fund may routinely trade with bid-offer spreads that may be significant. There can be no guarantee that the Fund’s investments could ultimately be realized at the Fund’s valuation of such investments. In addition, the Fund’s compliance with the asset diversification tests applicable to regulated investment companies depends on the fair market values of the Fund’s assets, and, accordingly, a challenge to the valuations ascribed by the Fund could affect its ability to comply with those tests or require it to pay penalty taxes in order to cure a violation thereof. The Fund’s NAV per share is a critical component in several operational matters including computation of advisory and services fees and determination of the price at which a tender offer will be made. Consequently, variance in the valuation of the Fund’s investments will impact, positively or negatively, the fees and expenses shareholders will pay. Reliance on the Advisor and Sub-Advisor The Fund is dependent upon services and resources provided by the Advisors, and therefore the Advisors’ parent, BlackRock. The Advisors are not required to devote their full time to the business of the Fund and there is no guarantee or requirement that any investment professional or other employee of the Advisors will allocate a substantial portion of his or her time to the Fund. The loss of one or more individuals involved with the Advisors could have a material adverse effect on the performance or the continued operation of the Fund. For additional information on the Advisor, the Sub-Advisor and BlackRock, see “Management of the Fund—Investment Advisor and Sub-Advisor.” Reliance on Service Providers Risk The Fund must rely upon the performance of service providers to perform certain functions, which may include functions that are integral to the Fund’s operations and financial performance. Failure by any service provider to carry out its obligations to the Fund in accordance with the terms of its appointment, to exercise due care and skill or to perform its obligations to the Fund at all as a result of insolvency, bankruptcy or other causes could have a material adverse effect on the Fund’s performance and returns to shareholders. The termination of the Fund’s relationship with any service provider, or any delay in appointing a replacement for such service provider, could materially disrupt the business of the Fund and could have a material adverse effect on the Fund’s performance and returns to shareholders. Information Technology Systems Risk The Fund is dependent on the Advisors for certain management services as well as back-office functions. The Advisors depend on information technology systems in order to assess investment opportunities, strategies and markets and to monitor and control risks for the Fund. It is possible that a failure of some kind which causes disruptions to these information technology systems could materially limit the Advisors’ ability to adequately assess and adjust investments, formulate strategies and provide adequate risk control. Any such information technology-related difficulty could harm the performance of the Fund. Further, failure of the back-office functions of the Advisors to process trades in a timely fashion could prejudice the investment performance of the Fund. Cyber Security Risk With the increased use of technologies such as the Internet to conduct business, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber-attacks include, but are not limited to, gaining unauthorized access to digital systems (e.g., through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber-attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites (i.e., efforts to make network services unavailable to intended users). Cyber security failures by or breaches of the Advisors and other service providers (including, but not limited to, fund accountants, custodians, transfer agents and administrators), and the issuers of securities in which the Fund invests, have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, interference with the Fund’s ability to calculate its NAV, impediments to trading, the inability of shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. While the Fund has established business continuity plans in the event of, and risk management systems to prevent, such cyber-attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. Furthermore, the Fund cannot control the cyber security plans and systems put in place by service providers to the Fund and issuers in which the Fund invests. As a result, the Fund or its shareholders could be negatively impacted. Misconduct of Employees and of Service Providers Risk Misconduct or misrepresentations by employees of the Advisor, the Sub-Advisor or the Fund’s service providers could cause significant losses to the Fund. Employee misconduct may include binding the Fund to transactions that exceed authorized limits or present unacceptable risks and unauthorized trading activities, concealing unsuccessful trading activities (which, in any case, may result in unknown and unmanaged risks or losses) or making misrepresentations regarding any of the foregoing. Losses could also result from actions by the Fund’s service providers, including, without limitation, failing to recognize trades and misappropriating assets. In addition, employees and service providers may improperly use or disclose confidential information, which could result in litigation or serious financial harm, including limiting the Fund’s business prospects or future marketing activities. Despite the Advisors’ due diligence efforts, misconduct and intentional misrepresentations may be undetected or not fully comprehended, thereby potentially undermining the Advisors’ due diligence efforts. As a result, no assurances can be given that the due diligence performed by the Advisors will identify or prevent any such misconduct. Special Risks for Holders of Rights There is a risk that performance of the Fund may result in the common shares purchasable upon exercise of the rights being less attractive to investors at the conclusion of the subscription period. This may reduce or eliminate the value of the rights. Investors who receive rights may find that there is no market to sell rights they do not wish to exercise. If investors exercise only a portion of the rights, common shares may trade at less favorable prices than larger offerings for similar securities. Portfolio Turnover Risk The Fund’s annual portfolio turnover rate may vary greatly from year to year, as well as within a given year. Portfolio turnover rate is not considered a limiting factor in the execution of investment decisions for the Fund. A higher portfolio turnover rate results in correspondingly greater brokerage commissions and other transactional expenses that are borne by the Fund. High portfolio turnover may result in an increased realization of net short-term capital gains by the Fund which, when distributed to common shareholders, will be taxable as ordinary income. Additionally, in a declining market, portfolio turnover may create realized capital losses. Anti-Takeover Provisions Risk The Fund’s Charter and Bylaws include provisions that could limit the ability of other entities or persons to acquire control of the Fund or convert the Fund to open-end status or to change the composition of the Board. The Fund’s Bylaws also contain a provision providing that the Board of Directors has adopted a resolution electing for the Fund to be subject to the provisions of the Maryland Control Share Acquisition Act (“MCSAA”). Such provisions may limit the ability of shareholders to sell their shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of the Fund. See “Certain Provisions in the Charter and Bylaws.” |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage [Text Block] |  | Effects of Leverage Assuming that leverage will represent approximately 31.2% of the Fund’s Managed Assets and that the Fund will bear expenses relating to that leverage at an average annual rate of 0.12%, the income generated by the Fund’s portfolio (net of estimated expenses) must exceed 0.04% in order to cover the expenses specifically related to the Fund’s use of leverage. Of course, these numbers are merely estimates used for illustration. Actual leverage expenses will vary frequently and may be significantly higher or lower than the rate estimated above. The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effect of leverage on common share total return, assuming investment portfolio total returns (comprised of income and changes in the value of investments held in the Fund’s portfolio) of (10)%, (5)%, 0%, 5% and 10%. These assumed investment portfolio returns are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Fund. The table further reflects the use of leverage representing 31.2% of the Fund’s Managed Assets and an assumed annual cost of leverage of 0.12%.
Assumed Portfolio Total Return (Net of Expenses) |  |  | (10.00 | )% |  |  | (5.00 | )% |  |  | 0 | % |  |  | 5.00 | % |  |  | 10.00 | %
Common Share Total Return |  |  | (14.6 | ) % |  |  | (7.3 | )% |  |  | (0.1 | )% |  |  | 7.2 | % |  |  | 14.5 | %
Common share total return is composed of two elements: the common share dividends paid by the Fund (the amount of which is largely determined by the net investment income of the Fund after paying for any leverage used by the Fund) and gains or losses on the value of the securities the Fund owns. As required by SEC rules, the table assumes that the Fund is 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 interest it receives on its investments is entirely offset by losses in the value of those securities. |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage [Table Text Block] |  |
Assumed Portfolio Total Return (Net of Expenses) |  |  | (10.00 | )% |  |  | (5.00 | )% |  |  | 0 | % |  |  | 5.00 | % |  |  | 10.00 | %
Common Share Total Return |  |  | (14.6 | ) % |  |  | (7.3 | )% |  |  | (0.1 | )% |  |  | 7.2 | % |  |  | 14.5 | %
Return at Minus Ten [Percent] |  | (14.60%) |  |  |  |  |  |  |  |  |  |  |
Return at Minus Five [Percent] |  | (7.30%) |  |  |  |  |  |  |  |  |  |  |
Return at Zero [Percent] |  | (0.10%) |  |  |  |  |  |  |  |  |  |  |
Return at Plus Five [Percent] |  | 7.20% |  |  |  |  |  |  |  |  |  |  |
Return at Plus Ten [Percent] |  | 14.50% |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage, Purpose [Text Block] |  | The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effect of leverage on common share total return, assuming investment portfolio total returns (comprised of income and changes in the value of investments held in the Fund’s portfolio) of (10)%, (5)%, 0%, 5% and 10%. These assumed investment portfolio returns are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Fund. The table further reflects the use of leverage representing 31.2% of the Fund’s Managed Assets and an assumed annual cost of leverage of 0.12%. |  |  |  |  |  |  |  |  |  |  |
Share Price [Table Text Block] |  | The following table sets forth, for the quarters indicated, the highest and lowest daily closing prices on the NYSE per common share, and 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 table also sets forth the number of common shares traded on the NYSE during the respective quarters. The amounts in the table have been adjusted to reflect the approximate effect of the Reverse Stock Split anticipated to take effect on October 18, 2022.
|  | NYSE Market Price Per Common Share |  |  | NAV per Common Share on Date of Market Price |  |  | Premium/ (Discount) on Date of Market Price |  |  | Trading |
During Quarter Ended |  | High |  |  | Low |  |  | High |  |  | Low |  |  | High |  |  | Low |  |  | Volume |
June 30, 2022 |  | $ | 15.36 |  |  | $ | 12.93 |  |  | $ | 15.51 |  |  | $ | 14.43 |  |  |  | (0.97 | ) |  |  | (10.33 | ) |  |  | 18,907,464 |
March 31, 2022 |  | $ | 16.92 |  |  | $ | 14.85 |  |  | $ | 16.89 |  |  | $ | 15.66 |  |  |  | 0.18 | % |  |  | (5.17 | )% |  |  | 21,937,873 |
December 31, 2021 |  | $ | 18.90 |  |  | $ | 16.95 |  |  | $ | 17.58 |  |  | $ | 16.95 |  |  |  | 7.51 | % |  |  | 0.00 | % |  |  | 16,500,738 |
September 30, 2021 |  | $ | 19.50 |  |  | $ | 17.88 |  |  | $ | 17.88 |  |  | $ | 17.67 |  |  |  | 9.06 | % |  |  | 1.21 | % |  |  | 13,508,607 |
June 30, 2021 |  | $ | 19.23 |  |  | $ | 18.27 |  |  | $ | 18.18 |  |  | $ | 18.39 |  |  |  | 5.78 | % |  |  | (0.65 | )% |  |  | 16,030,457 |
March 31, 2021 |  | $ | 18.51 |  |  | $ | 18.00 |  |  | $ | 18.54 |  |  | $ | 18.57 |  |  |  | (0.16 | )% |  |  | (3.07 | )% |  |  | 14,365,814 |
December 31, 2020 |  | $ | 18.54 |  |  | $ | 18.03 |  |  | $ | 18.90 |  |  | $ | 18.90 |  |  |  | (1.90 | )% |  |  | (4.60 | )% |  |  | 16,528,633 |
September 30, 2020 |  | $ | 18.69 |  |  | $ | 18.12 |  |  | $ | 18.99 |  |  | $ | 18.87 |  |  |  | (1.58 | )% |  |  | (3.97 | )% |  |  | 15,631,179 |
June 30, 2020 |  | $ | 18.66 |  |  | $ | 17.43 |  |  | $ | 18.96 |  |  | $ | 18.93 |  |  |  | (1.58 | )% |  |  | (7.92 | )% |  |  | 15,686,411 |
March 31, 2020 |  | $ | 18.60 |  |  | $ | 16.56 |  |  | $ | 19.20 |  |  | $ | 18.78 |  |  |  | (3.13 | )% |  |  | (11.82 | )% |  |  | 25,023,091 |
As of September 29, 2022, the NAV per common share of the Fund was $4.43 and the market price per common share was $4.08, representing a discount to NAV of (7.90)%. Common shares of the Fund have historically traded at both a premium and discount to NAV. As of September 22, 2022, the Fund has outstanding 63,912,834 common shares. Based on the number of common shares outstanding as of September 22, 2022, it is anticipated that the Fund will have approximately 21,304,278 common shares outstanding on October 18, 2022 following the Reverse Stock Split. |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock [Table Text Block] |  | DESCRIPTION OF CAPITAL STOCK The Fund is authorized to issue 200,000,000 shares of capital stock, par value $.01 per share, all of which shares are classified as common shares. Common Shares Common shares, when issued and outstanding, will be fully paid and non-assessable. Shareholders are entitled to share pro rata in the net assets of the Fund available for distribution to shareholders upon liquidation of the Fund. Shareholders are entitled to one vote for each share held. In the event that the Fund issues preferred shares and so long as any of the Fund’s preferred shares are outstanding, holders of common shares will not be entitled to receive any net income of or other distributions from the Fund unless all accumulated dividends on preferred shares have been paid, and unless asset coverage (as defined in the Investment Company Act) with respect to preferred shares would be at least 200% after giving effect to such distributions. See “Leverage—Preferred Shares.” The Fund will send unaudited reports at least semi-annually and audited annual financial statements to all of its shareholders. Unlike open-end funds, closed-end funds like the Fund do not continuously offer shares and do not provide daily redemptions. Rather, if a shareholder determines to buy additional common shares or sell shares already held, the shareholder may do so by trading through a broker on the NYSE or otherwise. Shares of closed-end investment companies frequently trade on an exchange at prices lower than NAV. Shares of closed-end investment companies like the Fund have during some periods traded at prices higher than NAV and during other periods have traded at prices lower than NAV. Because the market value of the common shares may be influenced by such factors as dividend levels (which are in turn affected by expenses), call protection on its portfolio securities, dividend stability, portfolio credit quality, the Fund’s NAV, relative demand for and supply of such shares in the market, general market and economic conditions, market sentiment and other factors beyond the control of the Fund, the Fund cannot assure you that its common shares will trade at a price equal to or higher than NAV in the future. The common shares are designed primarily for long-term investors and you should not purchase the common shares if you intend to sell them soon after purchase. See “Repurchase of Common Shares” below and “Repurchase of Common Shares” in the SAI. The Fund’s outstanding common shares are, and when issued, the common shares offered by this Prospectus will be, publicly held and listed and traded on the NYSE under the symbol “BKT.” The Fund determines its NAV on a daily basis. Preferred Shares In the event the Fund issues preferred shares, it is anticipated that such preferred shares will be issued in one or more series, with rights as determined by the Board of Directors, by action of the Board of Directors and with the approval of the shareholders. Under the Investment Company Act, the Fund is permitted to have outstanding more than one series of preferred shares so long as no single series has a priority over another series as to the distribution of assets of the Fund or the payment of dividends. Under the charter, holders of common shares will have no preemptive right to purchase any shares of preferred shares that might be issued. It is anticipated that the NAV per share of any preferred shares to be issued by the Fund will equal its original purchase price per share plus accumulated dividends per share. The Fund does not currently intend to issue preferred shares. Under the Investment Company Act, the Fund is not permitted to issue preferred shares unless immediately after such issuance the value of the Fund’s total assets is at least 200% of the liquidation value of the outstanding preferred shares ( i.e. , the liquidation value may not exceed 50% of the Fund’s total assets). In addition, the Fund is not permitted to declare any cash dividend or other distribution on its common shares unless, at the time of such declaration, the value of the Fund’s total assets is at least 200% of such liquidation value. If the Fund issues preferred shares, it may be subject to restrictions imposed by the guidelines of one or more rating agencies that may issue ratings for preferred shares issued by the Fund. These guidelines may impose asset coverage or portfolio composition requirements that are more stringent than those imposed on the Fund by the Investment Company Act. It is not anticipated that these covenants or guidelines would impede the Advisors from managing the Fund’s portfolio in accordance with the Fund’s investment objective and policies. Please see “Description of Capital Stock” in the SAI for more information. |  |  |  |  |  |  |  |  |  |  |
Other Security, Title [Text Block] |  | RIGHTS OFFERINGS |  |  |  |  |  |  |  |  |  |  |
Other Security, Description [Text Block] |  | RIGHTS OFFERINGS The Fund may in the future, and at its discretion, choose to make offerings of rights to its shareholders to purchase common shares. Rights may be issued independently or together with any other offered security and may or may not be transferable by the person purchasing or receiving the rights. In connection with a rights offering to shareholders, we would distribute certificates or other documentation ( i.e. , rights cards distributed in lieu of certificates) evidencing the rights and a Prospectus Supplement to our shareholders as of the record date that we set for determining the shareholders eligible to receive rights in such rights offering. Any such future rights offering will be made in accordance with the Investment Company Act. Under the laws of Maryland, the Board is authorized to approve rights offerings without obtaining shareholder approval. The staff of the SEC has interpreted the Investment Company Act as not requiring shareholder approval of a transferable rights offering to purchase common shares at a price below the then current NAV so long as certain conditions are met, including: (i) a good faith determination by a fund’s board that such offering would result in a net benefit to existing shareholders; (ii) the offering fully protects shareholders’ preemptive rights and does not discriminate among shareholders (except for the possible effect of not offering fractional rights); (iii) management uses its best efforts to ensure an adequate trading market in the rights for use by shareholders who do not exercise such rights; and (iv) the ratio of a transferable rights offering does not exceed one new share for each three rights held. The applicable Prospectus Supplement would describe the following terms of the rights in respect of which this Prospectus is being delivered:
| • |  | the period of time the offering would remain open;
| • |  | the underwriter or distributor, if any, of the rights and any associated underwriting fees or discounts applicable to purchases of the rights;
| • |  | the title of such rights;
| • |  | the exercise price for such rights (or method of calculation thereof);
| • |  | the number of such rights issued in respect of each share;
| • |  | the number of rights required to purchase a single share;
| • |  | the extent to which such rights are transferable and the market on which they may be traded if they are transferable;
| • |  | if applicable, a discussion of the material U.S. federal income tax considerations applicable to the issuance or exercise of such rights;
| • |  | the date on which the right to exercise such rights will commence, and the date on which such right will expire (subject to any extension);
| • |  | the extent to which such rights include an over-subscription privilege with respect to unsubscribed securities and the terms of such over-subscription privilege; and
| • |  | termination rights we may have in connection with such rights offering.
A certain number of rights would entitle the holder of the right(s) to purchase for cash such number of common shares at such exercise price as in each case is set forth in, or be determinable as set forth in, the Prospectus Supplement relating to the rights offered thereby. Rights would be exercisable at any time up to the close of business on the expiration date for such rights set forth in the Prospectus Supplement. After the close of business on the expiration date, all unexercised rights would become void. Upon expiration of the rights offering and the receipt of payment and the rights certificate or other appropriate documentation properly executed and completed and duly executed at the corporate trust office of the rights agent, or any other office indicated in the Prospectus Supplement, the common shares purchased as a result of such exercise will be issued as soon as practicable. To the extent permissible under applicable law, we may determine to offer any unsubscribed offered securities directly to persons other than shareholders, to or through agents, underwriters or dealers or through a combination of such methods, as set forth in the applicable Prospectus Supplement. |  |  |  |  |  |  |  |  |  |  |
Outstanding Securities [Table Text Block] |  | The following table provides the Fund’s authorized shares and common shares outstanding as of September 22, 2022.
Title of Class |  | Amount Authorized |  |  | Amount Held by Fund or for its Account |  |  | Amount Outstanding Exclusive of Amount held by Fund |
Common Shares |  |  | 200,000,000 |  |  |  | 0 |  |  |  | 63,912,834 |
Based on the number of common shares outstanding as of September 22, 2022, it is anticipated that the Fund will have approximately 21,304,278 common shares outstanding on October 18, 2022 following the Reverse Stock Split. |  |  |  |  |  |  |  |  |  |  |
General Risks [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | General Risks Please refer to the section of the Fund’s most recent annual report on Form N-CSR entitled “Investment Objectives, Policies and Risks—Risk Factors”, which is incorporated by reference herein, for a discussion of the general risks of investing in the Fund. |  |  |  |  |  |  |  |  |  |  |
WhenIssued, Forward Commitment and Delayed Delivery Transactions Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | When-Issued, Forward Commitment and Delayed Delivery Transactions Risk The Fund may purchase securities on a when-issued basis (including on a forward commitment or “TBA” (to be announced) basis) and may purchase or sell securities for delayed delivery. When-issued and delayed delivery transactions occur when securities are purchased or sold by the Fund with payment and delivery taking place in the future to secure an advantageous yield or price. Securities purchased on a when-issued or delayed delivery basis may expose the Fund to counterparty risk of default as well as the risk that securities may experience fluctuations in value prior to their actual delivery. The Fund will not accrue income with respect to a when-issued or delayed delivery security prior to its stated delivery date. Purchasing securities on a when-issued or delayed delivery basis can involve the additional risk that the price or yield available in the market when the delivery takes place may not be as favorable as that obtained in the transaction itself. |  |  |  |  |  |  |  |  |  |  |
Collateralized Debt Obligations Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Collateralized Debt Obligations Risk In addition to the typical risks associated with fixed-income securities and asset-backed securities, collateralized debt obligations (“CDOs”), including collateralized loan obligations, carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the risk that the collateral may default or decline in value or be downgraded, if rated by a nationally recognized statistical rating organization; (iii) the Fund may invest in tranches of CDOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; (v) the investment return achieved by the Fund could be significantly different than those predicted by financial models; (vi) the lack of a readily available secondary market for CDOs; (vii) the risk of forced “fire sale” liquidation due to technical defaults such as coverage test failures; and (viii) the CDO’s manager may perform poorly. |  |  |  |  |  |  |  |  |  |  |
Dollar Rolls Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Dollar Rolls Risk Dollar rolls involve the risk that the market value of the securities that the Fund is committed to buy may decline below the price of the securities the Fund has sold. These transactions may involve leverage. |  |  |  |  |  |  |  |  |  |  |
Short Sales Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Short Sales Risk Because making short sales in securities that it does not own exposes the Fund to the risks associated with those securities, such short sales involve speculative exposure risk. The Fund will incur a loss as a result of a short sale if the price of the security increases between the date of the short sale and the date on which the Fund replaces the security sold short. |  |  |  |  |  |  |  |  |  |  |
Investment Companies and ETFs Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Investment Companies and ETFs Risk Subject to the limitations set forth in the 1940 Act and the rules thereunder, the Fund may acquire shares in other investment companies and in ETFs, some of which may be affiliated investment companies. The market value of the shares of other investment companies and ETFs may differ from their net asset value. As an investor in investment companies and ETFs, the Fund would bear its ratable share of that entity’s expenses, including its investment advisory and administration fees, while continuing to pay its own advisory and administration fees and other expenses (to the extent not offset by the Advisor through waivers). As a result, shareholders will be absorbing duplicate levels of fees with respect to investments in other investment companies and ETFs (to the extent not offset by the Advisor through waivers). 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. |  |  |  |  |  |  |  |  |  |  |
Securities Lending Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Securities Lending Risk The Fund may lend securities to financial institutions. Securities lending involves exposure to certain risks, including operational risk (i.e., the risk of losses resulting from problems in the settlement and accounting process), “gap” risk (i.e., the risk of a mismatch between the return on cash collateral reinvestments and the fees the Fund has agreed to pay a borrower), foreign exchange risk (i.e., the risk of a shortfall at default when a cash collateral investment is denominated in a currency other than the currency of the assets being loaned due to movements in foreign exchange rates), and credit, legal, counterparty and market risks. If a securities lending counterparty were to default, the Fund would be subject to the risk of a possible delay in receiving collateral or in recovering the loaned securities, or to a possible loss of rights in the collateral. In the event a borrower does not return the Fund’s securities as agreed, the Fund may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated, plus the transaction costs incurred in purchasing replacement securities. This event could trigger adverse tax consequences for the Fund. The Fund could lose money if its short-term investment of the collateral declines in value over the period of the loan. Substitute payments for dividends received by the Fund for securities loaned out by the Fund will generally not be considered qualified dividend income. The securities lending agent will take the tax effects on shareholders of this difference into account in connection with the Fund’s securities lending program. Substitute payments received on tax-exempt securities loaned out will generally not be tax-exempt income. |  |  |  |  |  |  |  |  |  |  |
Inflation Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Inflation Risk Inflation risk is the risk that the value of assets or income from investment will be worth less in the future, as inflation decreases the value of money. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy. As inflation increases, the real value of the common shares and distributions on those shares can decline. In addition, during any periods of rising inflation, interest rates on any borrowings by the Trust would likely increase, which would tend to further reduce returns to the holders of common shares. |  |  |  |  |  |  |  |  |  |  |
Deflation Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Deflation Risk Deflation risk is the risk that prices throughout the economy decline over time, which may have an adverse effect on the market valuation of companies, their assets and their revenues. In addition, deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund’s portfolio. |  |  |  |  |  |  |  |  |  |  |
Swaps Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Swaps Risk Swaps are a type of derivative. Swap agreements involve the risk that the party with which the Fund has entered into the swap will default on its obligation to pay the Fund and the risk that the Fund will not be able to meet its obligations to pay the other party to the agreement. In order to seek to hedge the value of the Fund’s portfolio, to hedge against increases in the Fund’s cost associated with interest payments on any outstanding borrowings or to seek to increase the Fund’s return, the Fund may enter into swaps, including interest rate swap, total return swap (sometimes referred to as a “contract for difference”) and/or credit default swap transactions. In interest rate swap transactions, there is a risk that yields will move in the direction opposite of the direction anticipated by the Fund, which would cause the Fund to make payments to its counterparty in the transaction that could adversely affect Fund performance. In addition to the risks applicable to swaps generally (including counterparty risk, high volatility, illiquidity risk and credit risk), credit default swap transactions involve special risks because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). Historically, swap transactions have been individually negotiated non-standardized transactions entered into in OTC markets and have not been subject to the same type of government regulation as exchange-traded instruments. However, since the global financial crisis, the OTC derivatives markets have become subject to comprehensive statutes and regulations. In particular, in the United States, the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the “Dodd-Frank Act”), signed into law by President Obama on July 21, 2010, requires that certain derivatives with U.S. persons must be executed on a regulated market and a substantial portion of OTC derivatives must be submitted for clearing to regulated clearinghouses. As a result, swap transactions entered into by the Fund may become subject to various requirements applicable to swaps under the Dodd-Frank Act, including clearing, exchange-execution, reporting and recordkeeping requirements, which may make it more difficult and costly for the Fund to enter into swap transactions and may also render certain strategies in which the Fund might otherwise engage impossible or so costly that they will no longer be economical to implement. Furthermore, the number of counterparties that may be willing to enter into swap transactions with the Fund may also be limited if the swap transactions with the Fund are subject to the swap regulation under the Dodd-Frank Act. |  |  |  |  |  |  |  |  |  |  |
Risk Associated with Recent Market Events [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Risk Associated with Recent Market Events While interest rates have been historically low in recent years in the United States and abroad, inflation rates have recently risen significantly and the Federal Reserve and other central banks have recently begun raising interest rates to address inflation which, among other factors, has led to markets to experiencing high volatility. A significant increase in interest rates may cause a further decline in the market for equity securities and could lead to a recession. Further, regulators have expressed concern that rate increases may contribute to price volatility. The impact of inflation and the recent actions of the Federal Reserve have led to market volatility and may negatively affect the value of debt instruments held by the Fund and result in a negative impact on the Fund’s performance. See “Risks—Inflation Risk.” In addition, the current contentious domestic political environment, as well as political and diplomatic events in the United States and abroad, such as presidential elections in the United States or the U.S. government’s inability at times to agree on a long-term budget and deficit reduction plan, has in the past resulted, and may in the future result, in adverse consequences (including a government shutdown) to the U.S. regulatory landscape, the general market environment and/or investment sentiment, which could negatively impact the Fund’s investments and operations. Such adverse consequences may affect investor and/or consumer confidence and may adversely impact financial markets and the broader economy, potentially to a significant degree. In recent years, some countries, including the United States, have adopted and/or are considering the adoption of more protectionist trade policies. A rise in protectionist trade policies, and the possibility of changes to some international trade agreements, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, geopolitical and other risks, including environmental and public health, may add to instability in world economies and markets generally. Economies and financial markets throughout the world are becoming increasingly interconnected. As a result, whether or not the Fund invests in securities of issuers located in or with significant exposure to countries experiencing economic, political and/or financial difficulties, the value and liquidity of the Fund’s investments may be negatively affected by such events. 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. |  |  |  |  |  |  |  |  |  |  |
LIBOR Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | LIBOR Risk The Fund may be exposed to financial instruments that are tied to LIBOR to determine payment obligations, financing terms, hedging strategies or investment value. The Fund’s investments may pay interest at floating rates based on LIBOR or may be subject to interest caps or floors based on LIBOR. The Fund may also obtain financing at floating rates based on LIBOR. Derivative instruments utilized by the Fund may also reference LIBOR. The United Kingdom’s Financial Conduct Authority announced a phase out of LIBOR such that after June 30, 2023, the overnight, 1-month, 3-month, 6-month and 12-month U.S. dollar LIBOR settings will cease to be published or will no longer be representative. All other LIBOR settings and certain other interbank offered rates, such as the Euro Overnight Index Average (“EONIA”), ceased to be published or representative after December 31, 2021. The Fund may have investments linked to other interbank offered rates that may also cease to be published in the future. Various financial industry groups have been planning for the transition away from LIBOR, but there remain challenges to converting certain securities and transactions to a new reference rate (e.g., the Secured Overnight Financing Rate (“SOFR”), which is intended to replace the U.S. dollar LIBOR). Neither the effect of the LIBOR transition process nor its ultimate success can yet be known. The transition process might lead to increased volatility and illiquidity in markets for, and reduce the effectiveness of new hedges placed against, instruments whose terms currently include LIBOR. While some existing LIBOR-based instruments may contemplate a scenario where LIBOR is no longer available by providing for an alternative rate-setting methodology, there may be significant uncertainty regarding the effectiveness of any such alternative methodologies to replicate LIBOR. Not all existing LIBOR-based instruments may have alternative rate-setting provisions and there remains uncertainty regarding the willingness and ability of issuers to add alternative rate-setting provisions in certain existing instruments. Global regulators have advised market participants to cease entering into new contracts using LIBOR as a reference rate, and it is possible that investments in LIBOR-based instruments could invite regulatory scrutiny. In addition, a liquid market for newly issued instruments that use a reference rate other than LIBOR still may be developing. There may also be challenges for the Fund to enter into hedging transactions against such newly issued instruments until a market for such hedging transactions develops. All of the aforementioned may adversely affect the Fund’s performance or NAV. |  |  |  |  |  |  |  |  |  |  |
Market Disruption and Geopolitical Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Disruption and Geopolitical Risk The occurrence of events similar to those in recent years, such as the aftermath of the war in Iraq, instability in Afghanistan, Pakistan, Egypt, Libya, Syria, Russia, Ukraine and the Middle East, new and ongoing epidemics and pandemics of infectious diseases and other global health events, natural/environmental disasters, terrorist attacks in the United States and around the world, social and political discord, debt crises (such as the Greek crisis), sovereign debt downgrades, the Russian invasion of Ukraine, increasingly strained relations between the United States and a number of foreign countries, including historical adversaries, such as North Korea, Iran, China and Russia, and the international community generally, new and continued political unrest in various countries, such as Venezuela and Spain, the exit or potential exit of one or more countries from the EU or the EMU, and continued changes in the balance of political power among and within the branches of the U.S. government, among others, may result in market volatility, may have long term effects on the U.S. and worldwide financial markets, and may cause further economic uncertainties in the United States and worldwide. Russia launched a large-scale invasion of Ukraine on February 24, 2022. The extent and duration of the military action, resulting sanctions and resulting future market disruptions, including declines in its stock markets and the value of the ruble against the U.S. dollar, in the region are impossible to predict, but could be significant. Any such disruptions caused by Russian military action or other actions (including cyberattacks and espionage) or resulting actual and threatened responses to such activity, including purchasing and financing restrictions, boycotts or changes in consumer or purchaser preferences, sanctions, tariffs or cyberattacks on the Russian government, Russian companies or Russian individuals, including politicians, could have a severe adverse effect on Russia and the European region, including significant negative impacts on the Russian economy, the European economy and the markets for certain securities and commodities, such as oil and natural gas, and may likely have collateral impacts on such sectors globally as well as other sectors. How long such military action and related events will last cannot be predicted. China and the United States have each imposed tariffs on the other country’s products. These actions may cause 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. On January 31, 2020, the United Kingdom (“UK”) officially withdrew from the EU (commonly known as “Brexit”). The UK and EU reached a preliminary trade agreement, which became effective on January 1, 2021, regarding the terms of their future trading relationship relating principally to the trading of goods; however, negotiations are ongoing for matters not covered by the agreement, such as the trade of financial services. Due to uncertainty of the current political environment, it is not possible to foresee the form or nature of the future trading relationship between the UK and the EU. The longer term economic, legal, political and social framework to be put in place between the UK and the EU remains unclear and the ongoing political and economic uncertainty and periods of exacerbated volatility in both the UK and in wider European markets may continue for some time. In particular, Brexit may lead to a call for similar referendums in other European jurisdictions which may cause increased economic volatility in the European and global markets and may destabilize some or all of the other EU member countries. This uncertainty may have an adverse effect on the economy generally and on the ability of the Fund and its investments to execute their respective strategies, to receive attractive returns and/or to exit certain investments at an advantageous time or price. In particular, currency volatility may mean that the returns of the Fund and its investments are adversely affected by market movements and may make it more difficult, or more expensive, if the Fund elects to execute currency hedges. Potential decline in the value of the British Pound and/or the Euro against other currencies, along with the potential downgrading of the UK’s sovereign credit rating, may also have an impact on the performance of portfolio companies or investments located in the UK or Europe. In light of the above, no definitive assessment can currently be made regarding the impact that Brexit will have on the Fund, its investments or its organization more generally. Cybersecurity incidents affecting particular companies or industries may adversely affect the economies of particular countries, regions or parts of the world in which the Fund invests. The occurrence of any of these above events could have a significant adverse impact on the value and risk profile of the Fund’s portfolio. The Fund does not know how long the securities markets may be affected by similar events and cannot predict the effects of similar events in the future on the U.S. economy and securities markets. There can be no assurance that similar events and other market disruptions will not have other material and adverse implications. |  |  |  |  |  |  |  |  |  |  |
Regulation and Government Intervention Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Regulation and Government Intervention Risk Federal, state, and other governments, their regulatory agencies or self-regulatory organizations may take actions that affect the regulation of the issuers in which the Fund invests in ways that are unforeseeable. Legislation or regulation may also change the way in which the Fund is regulated. Such legislation or regulation could limit or preclude the Fund’s ability to achieve its investment objective. In light of popular, political and judicial focus on finance related consumer protection. Financial institution practices are also subject to greater scrutiny and criticism generally. In the case of transactions between financial institutions and the general public, there may be a greater tendency toward strict interpretation of terms and legal rights in favor of the consuming public, particularly where there is a real or perceived disparity in risk allocation and/or where consumers are perceived as not having had an opportunity to exercise informed consent to the transaction. In the event of conflicting interests between retail investors holding common shares of a closed-end investment company such as the Fund and a large financial institution, a court may similarly seek to strictly interpret terms and legal rights in favor of retail investors. The Fund may be affected by governmental action in ways that are not foreseeable, and there is a possibility that such actions could have a significant adverse effect on the Fund and its ability to achieve its investment objective. Investment Company Act Regulations The Fund is a registered closed-end management investment company and as such is subject to regulations under the Investment Company Act. Generally speaking, any contract or provision thereof that is made, or where performance involves a violation of the Investment Company Act or any rule or regulation thereunder is unenforceable by either party unless a court finds otherwise. |  |  |  |  |  |  |  |  |  |  |
Regulation as a Commodity Pool [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Regulation as a “Commodity Pool” The CFTC subjects advisers to registered investment companies to regulation by the CFTC if a fund that is advised by the investment adviser either (i) invests, directly or indirectly, more than a prescribed level of its liquidation value in CFTC-regulated futures, options and swaps (“CFTC Derivatives”), or (ii) markets itself as providing investment exposure to such instruments. To the extent the Fund uses CFTC Derivatives, it intends to do so below such prescribed levels and will not market itself as a “commodity pool” or a vehicle for trading such instruments. Accordingly, the Advisor has claimed an exclusion from the definition of the term “commodity pool operator” under the Commodity Exchange Act (“CEA”) pursuant to Rule 4.5 under the CEA. The Advisor is not, therefore, subject to registration or regulation as a “commodity pool operator” under the CEA in respect of the Fund. |  |  |  |  |  |  |  |  |  |  |
Failures of Futures Commission Merchants and Clearing Organizations Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Failures of Futures Commission Merchants and Clearing Organizations Risk The Fund is required to deposit funds to margin open positions in cleared derivative instruments (both futures and swaps) with a clearing broker registered as a “futures commission merchant” (“FCM”). The CEA requires an FCM to segregate all funds received from customers with respect to any orders for the purchase or sale of U.S. domestic futures contracts and cleared swaps from the FCM’s proprietary assets. Similarly, the CEA requires each FCM to hold in a separate secure account all funds received from customers with respect to any orders for the purchase or sale of foreign futures contracts and segregate any such funds from the funds received with respect to domestic futures contracts. However, all funds and other property received by an FCM from its customers are held by an FCM on a commingled basis in an omnibus account and amounts in excess of assets posted to the clearing organization may be invested by an FCM in certain instruments permitted under the applicable regulation. There is a risk that assets deposited by the Fund with any FCM as margin for futures contracts or commodity options may, in certain circumstances, be used to satisfy losses of other clients of the Fund’s FCM. In addition, the assets of the Fund posted as margin against both swaps and futures contracts may not be fully protected in the event of the FCM’s bankruptcy. |  |  |  |  |  |  |  |  |  |  |
Legal, Tax and Regulatory Risks [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Legal, Tax and Regulatory Risks Legal, tax and regulatory changes could occur that may have material adverse effects on the Fund. To qualify for the favorable U.S. federal income tax treatment generally accorded to RICs, the Fund must, among other things, derive in each taxable year at least 90% of (i) its net tax-exempt interest income, if any, and (ii) its gross income from certain prescribed sources and distribute for each taxable year at least 90% of its “investment company taxable income” (generally, ordinary income plus the excess, if any, of net short-term capital gain over net long-term capital loss). If for any taxable year the Fund does not qualify as a RIC, all of its taxable income for that year (including its net capital gain) would be subject to tax at regular corporate rates without any deduction for distributions to shareholders, and such distributions would be taxable as ordinary dividends to the extent of the Fund’s current and accumulated earnings and profits. The Biden presidential administration has called for significant changes to U.S. fiscal, tax, trade, healthcare, immigration, foreign, and government regulatory policy. In this regard, there is significant uncertainty with respect to legislation, regulation and government policy at the federal level, as well as the state and local levels. Recent events have created a climate of heightened uncertainty and introduced new and difficult-to-quantify macroeconomic and political risks with potentially far-reaching implications. There has been a corresponding meaningful increase in the uncertainty surrounding interest rates, inflation, foreign exchange rates, trade volumes and fiscal and monetary policy. To the extent the U.S. Congress or the current presidential administration implements changes to U.S. policy, those changes may impact, among other things, the U.S. and global economy, international trade and relations, unemployment, immigration, corporate taxes, healthcare, the U.S. regulatory environment, inflation and other areas. Although the Fund cannot predict the impact, if any, of these changes to the Fund’s business, they could adversely affect the Fund’s business, financial condition, operating results and cash flows. Until the Fund knows what policy changes are made and how those changes impact the Fund’s business and the business of the Fund’s competitors over the long term, the Fund will not know if, overall, the Fund will benefit from them or be negatively affected by them. The rules dealing with U.S. federal income taxation are constantly under review by persons involved in the legislative process and by the Internal Revenue Service and the U.S. Treasury Department. Revisions in U.S. federal tax laws and interpretations of these laws could adversely affect the tax consequences of your investment . |  |  |  |  |  |  |  |  |  |  |
Potential Conflicts of Interest of the Advisor, SubAdvisor and Others [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Potential Conflicts of Interest of the Advisor, Sub-Advisor and Others The investment activities of BlackRock, Inc. (“BlackRock”), the ultimate parent company of the Advisors, and its affiliates (including BlackRock and its subsidiaries (collectively, the “Affiliates”))in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BlackRock and its Affiliates provide investment management services to other funds and discretionary managed accounts that may follow investment programs similar to that of the Fund. Subject to the requirements of the Investment Company Act, BlackRock and its Affiliates intend to engage in such activities and may receive compensation from third parties for their services. None of BlackRock or its Affiliates are under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, BlackRock and its Affiliates may compete with the Fund for appropriate investment opportunities. The results of the Fund’s investment activities, therefore, may differ from those of an Affiliate or another account managed by BlackRock or an Affiliate, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates and other accounts achieve profits on their trading for proprietary or other accounts. BlackRock has adopted policies and procedures designed to address potential conflicts of interest. For additional information about potential conflicts of interest and the way in which BlackRock addresses such conflicts, please see “Conflicts of Interest” and “Management of the Fund—Portfolio Management—Potential Material Conflicts of Interest” in the SAI. |  |  |  |  |  |  |  |  |  |  |
Defensive Investing Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Defensive Investing Risk For defensive purposes, the Fund may allocate assets into cash or short-term fixed-income securities without limitation. In doing so, the Fund may succeed in avoiding losses but may otherwise fail to achieve its investment objective. Further, the value of short-term fixed-income securities may be affected by changing interest rates and by changes in credit ratings of the investments. If the Fund holds cash uninvested it will be subject to the credit risk of the depository institution holding the cash. |  |  |  |  |  |  |  |  |  |  |
DecisionMaking Authority Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Decision-Making Authority Risk Investors have no authority to make decisions or to exercise business discretion on behalf of the Fund, except as set forth in the Fund’s governing documents. The authority for all such decisions is generally delegated to the Board, which in turn, has delegated the day-to-day management of the Fund’s investment activities to the Advisors, subject to oversight by the Board. |  |  |  |  |  |  |  |  |  |  |
Management Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Management Risk The Fund is subject to management risk because it is an actively managed investment portfolio. The Advisors and the individual portfolio managers will apply investment techniques and risk analyses in making investment decisions for the Fund, but there can be no guarantee that these will produce the desired results. The Fund may be subject to a relatively high level of management risk because the Fund may invest in derivative instruments, which may be highly specialized instruments that require investment techniques and risk analyses different from those associated with equities and bonds. |  |  |  |  |  |  |  |  |  |  |
Valuation Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Valuation Risk The Fund is subject to valuation risk, which is the risk that one or more of the securities in which the Fund invests are valued at prices that the Fund is unable to obtain upon sale due to factors such as incomplete data, market instability or human error. The Advisor may use an independent pricing service or prices provided by dealers to value securities at their market value. Because the secondary markets for certain investments may be limited, such instruments may be difficult to value. See “Net Asset Value.” When market quotations are not available, the Advisor may price such investments pursuant to a number of methodologies, such as computer-based analytical modeling or individual security evaluations. These methodologies generate approximations of market values, and there may be significant professional disagreement about the best methodology for a particular type of financial instrument or different methodologies that might be used under different circumstances. In the absence of an actual market transaction, reliance on such methodologies is essential, but may introduce significant variances in the ultimate valuation of the Fund’s investments. Technological issues and/or errors by pricing services or other third-party service providers may also impact the Fund’s ability to value its investments and the calculation of the Fund’s NAV. When market quotations are not readily available or are believed by the Advisor to be unreliable, the Advisor will fair value the Fund’s investments in accordance with its policies and procedures. Fair value represents a good faith approximation of the value of an asset or liability. The fair value of an asset or liability held by the Fund is the amount the Fund might reasonably expect to receive from the current sale of that asset or the cost to extinguish that liability in an arm’s-length transaction. Fair value pricing may require determinations that are inherently subjective and inexact about the value of a security or other asset. As a result, there can be no assurance that fair value priced assets will not result in future adjustments to the prices of securities or other assets, or that fair value pricing will reflect a price that the Fund is able to obtain upon sale, and it is possible that the fair value determined for a security or other asset will be materially different from quoted or published prices, from the prices used by others for the same security or other asset and/or from the value that actually could be or is realized upon the sale of that security or other asset. For example, the Fund’s NAV could be adversely affected if the Fund’s determinations regarding the fair value of the Fund’s investments were materially higher than the values that the Fund ultimately realizes upon the disposal of such investments. Where market quotations are not readily available, valuation may require more research than for more liquid investments. In addition, elements of judgment may play a greater role in valuation in such cases than for investments with a more active secondary market because there is less reliable objective data available. Because of overall size, duration and maturities of positions held by the Fund, the value at which its investments can be liquidated may differ, sometimes significantly, from the interim valuations obtained by the Fund. In addition, the timing of liquidations may also affect the values obtained on liquidation. Securities held by the Fund may routinely trade with bid-offer spreads that may be significant. There can be no guarantee that the Fund’s investments could ultimately be realized at the Fund’s valuation of such investments. In addition, the Fund’s compliance with the asset diversification tests applicable to regulated investment companies depends on the fair market values of the Fund’s assets, and, accordingly, a challenge to the valuations ascribed by the Fund could affect its ability to comply with those tests or require it to pay penalty taxes in order to cure a violation thereof. The Fund’s NAV per share is a critical component in several operational matters including computation of advisory and services fees and determination of the price at which a tender offer will be made. Consequently, variance in the valuation of the Fund’s investments will impact, positively or negatively, the fees and expenses shareholders will pay. |  |  |  |  |  |  |  |  |  |  |
Reliance on the Advisor and SubAdvisor [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Reliance on the Advisor and Sub-Advisor The Fund is dependent upon services and resources provided by the Advisors, and therefore the Advisors’ parent, BlackRock. The Advisors are not required to devote their full time to the business of the Fund and there is no guarantee or requirement that any investment professional or other employee of the Advisors will allocate a substantial portion of his or her time to the Fund. The loss of one or more individuals involved with the Advisors could have a material adverse effect on the performance or the continued operation of the Fund. For additional information on the Advisor, the Sub-Advisor and BlackRock, see “Management of the Fund—Investment Advisor and Sub-Advisor.” |  |  |  |  |  |  |  |  |  |  |
Reliance on Service Providers Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Reliance on Service Providers Risk The Fund must rely upon the performance of service providers to perform certain functions, which may include functions that are integral to the Fund’s operations and financial performance. Failure by any service provider to carry out its obligations to the Fund in accordance with the terms of its appointment, to exercise due care and skill or to perform its obligations to the Fund at all as a result of insolvency, bankruptcy or other causes could have a material adverse effect on the Fund’s performance and returns to shareholders. The termination of the Fund’s relationship with any service provider, or any delay in appointing a replacement for such service provider, could materially disrupt the business of the Fund and could have a material adverse effect on the Fund’s performance and returns to shareholders. |  |  |  |  |  |  |  |  |  |  |
Information Technology Systems Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Information Technology Systems Risk The Fund is dependent on the Advisors for certain management services as well as back-office functions. The Advisors depend on information technology systems in order to assess investment opportunities, strategies and markets and to monitor and control risks for the Fund. It is possible that a failure of some kind which causes disruptions to these information technology systems could materially limit the Advisors’ ability to adequately assess and adjust investments, formulate strategies and provide adequate risk control. Any such information technology-related difficulty could harm the performance of the Fund. Further, failure of the back-office functions of the Advisors to process trades in a timely fashion could prejudice the investment performance of the Fund. |  |  |  |  |  |  |  |  |  |  |
Cyber Security Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Cyber Security Risk With the increased use of technologies such as the Internet to conduct business, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber-attacks include, but are not limited to, gaining unauthorized access to digital systems (e.g., through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber-attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites (i.e., efforts to make network services unavailable to intended users). Cyber security failures by or breaches of the Advisors and other service providers (including, but not limited to, fund accountants, custodians, transfer agents and administrators), and the issuers of securities in which the Fund invests, have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, interference with the Fund’s ability to calculate its NAV, impediments to trading, the inability of shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. While the Fund has established business continuity plans in the event of, and risk management systems to prevent, such cyber-attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. Furthermore, the Fund cannot control the cyber security plans and systems put in place by service providers to the Fund and issuers in which the Fund invests. As a result, the Fund or its shareholders could be negatively impacted. |  |  |  |  |  |  |  |  |  |  |
Misconduct of Employees and of Service Providers Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Misconduct of Employees and of Service Providers Risk Misconduct or misrepresentations by employees of the Advisor, the Sub-Advisor or the Fund’s service providers could cause significant losses to the Fund. Employee misconduct may include binding the Fund to transactions that exceed authorized limits or present unacceptable risks and unauthorized trading activities, concealing unsuccessful trading activities (which, in any case, may result in unknown and unmanaged risks or losses) or making misrepresentations regarding any of the foregoing. Losses could also result from actions by the Fund’s service providers, including, without limitation, failing to recognize trades and misappropriating assets. In addition, employees and service providers may improperly use or disclose confidential information, which could result in litigation or serious financial harm, including limiting the Fund’s business prospects or future marketing activities. Despite the Advisors’ due diligence efforts, misconduct and intentional misrepresentations may be undetected or not fully comprehended, thereby potentially undermining the Advisors’ due diligence efforts. As a result, no assurances can be given that the due diligence performed by the Advisors will identify or prevent any such misconduct. |  |  |  |  |  |  |  |  |  |  |
Special Risks for Holders of Rights [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Special Risks for Holders of Rights There is a risk that performance of the Fund may result in the common shares purchasable upon exercise of the rights being less attractive to investors at the conclusion of the subscription period. This may reduce or eliminate the value of the rights. Investors who receive rights may find that there is no market to sell rights they do not wish to exercise. If investors exercise only a portion of the rights, common shares may trade at less favorable prices than larger offerings for similar securities. |  |  |  |  |  |  |  |  |  |  |
Portfolio Turnover Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Portfolio Turnover Risk The Fund’s annual portfolio turnover rate may vary greatly from year to year, as well as within a given year. Portfolio turnover rate is not considered a limiting factor in the execution of investment decisions for the Fund. A higher portfolio turnover rate results in correspondingly greater brokerage commissions and other transactional expenses that are borne by the Fund. High portfolio turnover may result in an increased realization of net short-term capital gains by the Fund which, when distributed to common shareholders, will be taxable as ordinary income. Additionally, in a declining market, portfolio turnover may create realized capital losses. |  |  |  |  |  |  |  |  |  |  |
AntiTakeover Provisions Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Anti-Takeover Provisions Risk The Fund’s Charter and Bylaws include provisions that could limit the ability of other entities or persons to acquire control of the Fund or convert the Fund to open-end status or to change the composition of the Board. The Fund’s Bylaws also contain a provision providing that the Board of Directors has adopted a resolution electing for the Fund to be subject to the provisions of the Maryland Control Share Acquisition Act (“MCSAA”). Such provisions may limit the ability of shareholders to sell their shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of the Fund. See “Certain Provisions in the Charter and Bylaws.” |  |  |  |  |  |  |  |  |  |  |
Business Contact [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | 55 East 52nd Street |  |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | New York |  |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | NY |  |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 10055 |  |  |  |  |  |  |  |  |  |  |
Contact Personnel Name |  | John M. Perlowski, President |  |  |  |  |  |  |  |  |  |  |
Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Basis of Transaction Fees, Note [Text Block] |  | as a percentage of net assets attributable to common shares |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Lowest Price or Bid |  |  |  | $ 12.93 | $ 14.85 | $ 16.95 | $ 17.88 | $ 18.27 | $ 18 | $ 18.03 | $ 18.12 | $ 17.43 | $ 16.56
Highest Price or Bid |  |  |  | 15.36 | 16.92 | 18.9 | 19.5 | 19.23 | 18.51 | 18.54 | 18.69 | 18.66 | 18.6
Lowest Price or Bid, NAV |  |  |  | 14.43 | 15.66 | 16.95 | 17.67 | 18.39 | 18.57 | 18.9 | 18.87 | 18.93 | 18.78
Highest Price or Bid, NAV |  |  |  | $ 15.51 | $ 16.89 | $ 17.58 | $ 17.88 | $ 18.18 | $ 18.54 | $ 18.9 | $ 18.99 | $ 18.96 | $ 19.2
Highest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | (0.97%) | 0.18% | 7.51% | 9.06% | 5.78% | (0.16%) | (1.90%) | (1.58%) | (1.58%) | (3.13%)
Lowest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | (10.33%) | (5.17%) | 0.00% | 1.21% | (0.65%) | (3.07%) | (4.60%) | (3.97%) | (7.92%) | (11.82%)
Latest Share Price |  | $ 4.08 |  |  |  |  |  |  |  |  |  |  |
Latest Premium (Discount) to NAV [Percent] |  | (7.90%) |  |  |  |  |  |  |  |  |  |  |
Latest NAV |  | $ 4.43 |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Common Shares |  |  |  |  |  |  |  |  |  |
Outstanding Security, Authorized [Shares] |  |  | 200,000,000 |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 0 |  |  |  |  |  |  |  |  |  |
Outstanding Security, Not Held [Shares] |  |  | 63,912,834 |  |  |  |  |  |  |  |  |  |
[1] | If the common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load and the estimated offering expenses. Fund shareholders will pay all offering expenses involved with an offering.
[2] | The Reinvestment Plan Agent’s (as defined below under “Dividend Reinvestment Plan”) fees for the handling of the reinvestment of dividends will be paid by the Fund. However, you 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. You will also be charged a $2.50 sales fee and pay a $0.15 per share fee if you direct the Reinvestment Plan Agent to sell your 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] | The Fund and the Advisor have entered into a fee waiver agreement (the “Fee Waiver Agreement”), pursuant to which the Advisor has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets attributable to investments in any equity and fixed-income mutual funds and ETFs managed by the Advisor or its affiliates that have a contractual management fee, through June 30, 2024. In addition, pursuant to the Fee Waiver Agreement, the Advisor has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to the Advisor indirectly through its investment in money market funds managed by the Advisor or its affiliates, through June 30, 2024. The Fee Waiver Agreement may be terminated at any time, without the payment of any penalty, only by the Fund (upon the vote of a majority of the Directors who are not “interested persons” (as defined in the Investment Company Act) of the Fund (the “Independent Directors”) or a majority of the outstanding voting securities of the Fund), upon 90 days’ written notice by the Fund to the Advisor.
[4] | The Fund currently pays the Advisor a monthly fee at an annual contractual investment management fee rate of 0.65% of the average weekly value of the Fund’s Net Assets. “Net Assets” means the total assets of the Fund minus the sum of its accrued liabilities (including the aggregate indebtedness constituting financial leverage).
[5] | Assumes the use of leverage in the form of reverse repurchase agreements representing 32.6% of Managed Assets at an annual interest expense to the Fund of 0.12% which is based on current market conditions. The actual amount of interest expense borne by the Fund will vary over time in accordance with the level of the Fund’s use of reverse repurchase agreements and variations in market interest rates. Interest expense is required to be treated as an expense of the Fund for accounting purposes.

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