Eaton Vance Tax-Managed Buy-Write Opportunities Fund (ETV)
Company Profile
| N-2 - USD ($) | 3 Months Ended | 12 Months Ended | ||||||||
| Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022 | Sep. 30, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2023 | ||
| Cover [Abstract] | ||||||||||
| Entity Central Index Key | 0001322436 | |||||||||
| Amendment Flag | false | |||||||||
| Document Type | N-CSR | |||||||||
| Entity Registrant Name | Eaton Vance Tax-Managed Buy-Write Opportunities Fund | |||||||||
| Fee Table [Abstract] | ||||||||||
| Shareholder Transaction Expenses [Table Text Block] | Common shareholder transaction expenses Sales load paid by you (as a percentage of offering price) — 1 Offering expenses (as a percentage of offering price) None 2 Dividend reinvestment plan fees $5.00 3 1 If common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load. 2 Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering. 3 You will be charged a $5.00 service charge and pay brokerage charges if you direct the plan agent to sell your common shares held in a dividend reinvestment account. | |||||||||
| Sales Load [Percent] | [1] | 0% | ||||||||
| Dividend Reinvestment and Cash Purchase Fees | [2] | $ 5 | ||||||||
| Other Transaction Expenses [Abstract] | ||||||||||
| Other Transaction Expenses [Percent] | [3] | 0% | ||||||||
| Annual Expenses [Table Text Block] | Annual expenses Percentage of net assets 4 Investment adviser fee 1.00% 5 Other expenses 0.09 Total annual Fund operating expenses 1.09% 4 Stated as a percentage of average net assets attributable to common shares for the year ended December 31, 2023. 5 The investment adviser fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. | |||||||||
| Management Fees [Percent] | [4],[5] | 1% | ||||||||
| Other Annual Expenses [Abstract] | ||||||||||
| Other Annual Expenses [Percent] | [4] | 0.09% | ||||||||
| Total Annual Expenses [Percent] | [4] | 1.09% | ||||||||
| Expense Example [Table Text Block] | Example The following Example illustrates the expenses that common shareholders would pay on a $1,000 investment in common shares, assuming (i) total annual expenses of 1.09% of net assets attributable to common shares in years 1 through 10; (ii) a 5% annual return; and (iii) all distributions are reinvested at NAV: 1 Year 3 Years 5 Years 10 Years $11 $35 $60 $133 The above table and example and the assumption in the example of a 5% annual return are required by regulations of the U.S. Securities and Exchange Commission (“SEC”) that are applicable to all investment companies; the assumed 5% annual return is not a prediction of, and does not represent, the projected or actual performance of the Fund’s common shares. In addition, while the example assumes reinvestment of all dividends and distributions at NAV, participants in the Fund’s dividend reinvestment plan may receive common shares purchased or issued at a price or value different from NAV. The example does not include sales load or estimated offering costs, which would cause the expenses shown in the example to increase. The example should not be considered a representation of past or future expenses, and the Fund’s actual expenses may be greater or less than those shown. Moreover, the Fund’s actual rate of return may be greater or less than the hypothetical 5% return shown in the example. | |||||||||
| Expense Example, Year 01 | $ 11 | |||||||||
| Expense Example, Years 1 to 3 | 35 | |||||||||
| Expense Example, Years 1 to 5 | 60 | |||||||||
| Expense Example, Years 1 to 10 | $ 133 | |||||||||
| Purpose of Fee Table , Note [Text Block] | The purpose of the table below is to help you understand all fees and expenses that you, as a common shareholder, would bear directly or indirectly. The table shows Fund expenses as a percentage of net assets attributable to common shares for the year ended December 31, 2023. | |||||||||
| Basis of Transaction Fees, Note [Text Block] | as a percentage of offering price | |||||||||
| Other Transaction Fees, Note [Text Block] | Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering. | |||||||||
| Management Fee not based on Net Assets, Note [Text Block] | The investment adviser fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. | |||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Investment Objectives and Practices [Text Block] | Investment Objectives. The Fund’s primary investment objective is to provide current income and gains, with a secondary objective of capital appreciation. In pursuing its investment objectives, the Fund will evaluate returns on an after-tax basis, seeking to minimize and defer shareholder federal income taxes. Principal Strategies. Under normal market conditions, the Fund’s investment program consists primarily of: (1) owning a diversified portfolio of common stocks, a segment of which (“Segment One”) seeks to exceed the total return performance of the S&P 500® Composite Stock Price Index (the “S&P 500®”) and a segment of which (“Segment Two”) seeks to exceed the total return performance of the NASDAQ-100® Index (the “NASDAQ-100®”); and (2) selling on a continuous basis S&P 500® call options on at least 80% of the value of Segment One and NASDAQ-100® call options on at least 80% of the value of Segment Two. Under normal market conditions, the Fund invests at least 80% of its total assets in a diversified portfolio of common stocks, designated segments of which seek to exceed the total return performance of the S&P 500® and the NASDAQ-100®. Due to tax considerations, the Fund intends to limit the overlap between its stock portfolio holdings (and any subset thereof) and each of the S&P 500® and the NASDAQ-100® to less than 70% on an ongoing basis. The Fund’s stock holdings may include stocks not included in either index. Under normal market conditions, the Fund expects to sell on a continuous basis S&P 500® call options on at least 80% of the value of Segment One and NASDAQ-100® call options on at least 80% of the value of Segment Two. Under normal market conditions, at least 80% of the value of the Fund’s total assets will be subject to written index call options. The Fund invests primarily in common stocks of U.S. issuers. The Fund may invest up to 10% of its total assets in securities of foreign issuers, including American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and European Depositary Receipts (“EDRs”). The Fund may invest up to 5% of its total assets in securities of emerging market issuers. The Fund normally expects that its assets will be invested across a broad range of industries and market sectors. Investing in NASDAQ-100® stocks may result in significant exposure to companies in the technology and communication services sectors. The Fund may invest a portion of its assets in stocks of mid-capitalization companies. In addition to writing index call options, the Fund may invest up to 20% of its total assets in derivative instruments acquired for hedging, risk management and investment purposes (to gain exposure to securities, securities markets, markets indices and/or currencies consistent with its investment objectives and policies), provided that no more than 10% of the Fund’s total assets may be invested in such derivative instruments acquired for non-hedging purposes. To seek to protect against price declines in securities holdings with large accumulated gains, the Fund may use various hedging techniques (such as the purchase and sale of futures contracts on stocks and stock indices and options thereon, equity swaps, covered short sales, forward sales of stocks and the purchase and sale of forward currency exchange contracts and currency futures). During unusual market conditions, the Fund may invest up to 100% of its assets in cash or cash equivalent temporarily, which may be inconsistent with its investment objectives, principal strategies and other policies. | |||||||||
| Risk Factors [Table Text Block] | Principal Risks Market Discount Risk. As with any security, the market value of the common shares may increase or decrease from the amount initially paid for the common shares. The Fund’s common shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Fund’s NAV may decrease. Investment and Market Risk. An investment in common shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in common shares represents an indirect investment in the securities owned by the Fund, which are generally traded on a securities exchange or in the over-the-counter markets. The value of these securities, like other market investments, may move up or down, sometimes rapidly and unpredictably. Because the Fund intends to sell index call options on a continuous basis on at least 80% of the value of its total assets, the Fund’s appreciation potential from equity market performance will be limited. The common shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. Issuer Risk. The value of securities held by the Fund may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund’s equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels. Option Strategy Risk. The Fund’s option strategy seeks to take advantage of, and its effectiveness is dependent on, a general excess of option price implied volatilities for the S&P 500® and NASDAQ 100® indices over realized index volatilities. This market observation is often attributed to an excess of natural buyers over natural sellers of S&P 500® and NASDAQ 100® index options. There can be no assurance that this imbalance will apply in the future over specific periods or generally. It is possible that the imbalance could decrease or be eliminated by actions of investors, including the Fund, that employ strategies seeking to take advantage of the imbalance, which could have an adverse effect on the Fund’s ability to achieve its investment objective. Risk of Selling Index Call Options. The purchaser of an index call option has the right to any appreciation in the value of the index over the exercise price of the call option as of the valuation date of the option. Because their exercise is settled in cash, sellers of index call options such as the Fund cannot provide in advance for their potential settlement obligations by acquiring and holding the underlying securities. The Fund intends to mitigate the risks of its options activities by holding a diversified portfolio of stocks that the Fund’s investment adviser believes collectively approximate the characteristics of the indices on which options are written. The Fund will not, however, hold stocks that fully replicate the indices on which it writes call options. Due to tax considerations, the Fund intends to limit the overlap between its stock holdings (and any subset thereof) and each index on which it has outstanding options positions to less than 70% on an ongoing basis. The Fund’s stock holdings will normally include stocks not included in the index on which it writes call options. Consequently, the Fund bears the risk that the performance of its stock portfolio will vary from the performance of the indices on which it writes call options. As the writer of index call options, the Fund will forgo, during the option’s life, the opportunity to profit from increases in the value of the applicable index above the sum of the option premium received and the exercise price of the call option, but retains the risk of loss, minus the option premium received, should the value of the applicable index decline. When a call option is exercised, the Fund will be required to deliver an amount of cash determined by the excess of the value of the applicable index at contract termination over the exercise price of the option. Thus, the exercise of index call options sold by the Fund may require the Fund to sell portfolio securities to generate cash at inopportune times or for unattractive prices. The trading price of options may be adversely affected if the market for such options becomes less liquid or smaller. The Fund may close out a call option by buying the option instead of letting it expire or be exercised. There can be no assurance that a liquid market will exist when the Fund seeks to close out a call option position by buying the option. The trading price of options may be adversely affected if the market for such options becomes less liquid or smaller. The Fund may close out a call option by buying the option instead of letting it expire or be exercised. There can be no assurance that a liquid market will exist when the Fund seeks to close out a call option position by buying the option. Derivatives Risk. The Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment. Tax-Sensitive Investing Risk. The Fund may hold a security in order to achieve more favorable tax-treatment or to sell a security in order to create tax losses. The Fund’s utilization of various tax-management techniques may be curtailed or eliminated by tax legislation, regulation or interpretations. The Fund may not be able to minimize taxable distributions to shareholders and a portion of the Fund’s distributions may be taxable. Tax Risk. Although the Fund seeks to minimize and defer the federal income taxes incurred by common shareholders in connection with their investment in the Fund, there can be no assurance that it will be successful in this regard. Market conditions may limit the Fund’s ability to generate tax losses or to generate income taxed at favorable tax rates. The Fund’s tax-managed strategy may cause the Fund to hold a security in order to achieve more favorable tax-treatment or to sell a security in order to create tax losses. The Fund’s ability to utilize various tax-management techniques may be curtailed or eliminated in the future by tax legislation, regulation or interpretations. Distributions paid on the Common Shares may be characterized variously as net investment income (taxable at ordinary income rates), qualified dividends and capital gains dividends (each taxable at long-term capital gains rates) or return of capital (not currently taxable). The ultimate tax characterization of the Fund’s distributions made in a calendar year may not finally be determined until after the end of that calendar year. Distributions to a common shareholder that are a return of capital will be tax free up to the amount of the common shareholder’s current tax basis in his or her Common Shares, with any distribution amounts exceeding such basis treated as capital gain on a deemed sale of Common Shares. common shareholders are required to reduce their tax basis (not below zero) in Common Shares by the amount of tax-free return of capital distributions received, thereby increasing the amount of capital gain (or decreasing the amount of capital loss) to be recognized upon a later disposition of the Common Shares. In order for Fund distributions of qualified dividend income to be taxable at favorable long-term capital gains rates, the Fund must meet certain holding period and other requirements with respect to the dividend-paying stock in its portfolio, and a common shareholder must meet certain prescribed holding period and other requirements with respect to his or her Common Shares. If positions held by the Fund were treated as “straddles” for federal income tax purposes, dividends on such positions would not constitute qualified dividend income subject to favorable income tax treatment. Gain or loss on positions in a straddle are subject to special (and generally disadvantageous) rule. Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund’s investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States, and as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. Depositary receipts are subject to many of the risks associated with investing directly in foreign instruments, including the political and economic risks of the underlying issuer’s country and, in the case of depositary receipts traded on foreign markets, currency risk. Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain economic sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets. Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks. Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress. Interest Rate Risk. The premiums from writing index call options and amounts available for distribution from the Fund’s options activity may decrease in declining interest rate environments. The value of the Fund’s common stock investments may also be influenced by changes in interest rates. Higher yielding stocks and stocks of issuers whose businesses are substantially affected by changes in interest rates may be particularly sensitive to interest rate risk. Inflation Risk. Inflation risk is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the Common Shares and distributions thereon can decline. Dividend Capture Trading Risk. The use of dividend capture strategies will expose the Fund to higher portfolio turnover, increased trading costs and potential for capital loss or gain, particularly in the event of significant short-term price movements of stocks subject to dividend capture trading. Risk of Investing in Smaller and Mid-Sized Companies. The Fund may make investments in stocks of companies whose market capitalization is considered middle sized or “mid-cap.” Smaller and mid-sized companies often are newer or less established companies than larger companies. Investments in smaller and mid-sized companies carry additional risks because earnings of these companies tend to be less predictable; they often have limited product lines, markets, distribution channels or financial resources; and the management of such companies may be dependent upon one or a few key people. The market movements of equity securities of smaller and mid-sized companies may be more abrupt or erratic than the market movements of equity securities of larger, more established companies or the stock market in general. Historically, smaller and mid-sized companies have sometimes gone through extended periods when they did not perform as well as larger companies. In addition, equity securities of smaller and mid-sized companies generally are less liquid than those of larger companies. This means that the Fund could have greater difficulty selling such securities at the time and price that the Fund would like. Technology Risk. The technology industries can be significantly affected by obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants and general economic conditions. Risks of “Growth” Stock Investing. The Fund invests substantially in stocks with “growth” characteristics. Growth stocks can react differently to issuer, political, market and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, growth stocks tend to be sensitive to changes in their earnings and more volatile than other types of stocks. Leverage Risk. Certain Fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to an underlying reference instrument. Leverage can also result from borrowings or issuance of preferred shares. Leverage can increase both the risk and return potential of the Fund. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations. Leverage may cause the Fund’s NAV to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the Fund’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment. Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns. Recent Market Conditions. The outbreak of COVID-19 and efforts to contain its spread resulted in closing borders, enhanced health screenings, changes to healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this coronavirus and the effects of other infectious illness outbreaks, epidemics or pandemics may be short term or may continue for an extended period of time. Health crises caused by outbreaks of disease, such as the coronavirus outbreak, may exacerbate other pre-existing political, social and economic risks and disrupt normal market conditions and operations. For example, a global pandemic or other widespread health crisis could cause substantial market volatility and exchange trading suspensions and closures. In addition, the increasing interconnectedness of markets around the world may result in many markets being affected by events or conditions in a single country or region or events affecting a single or small number of issuers. The coronavirus outbreak and public and private sector responses thereto have led to large portions of the populations of many countries working from home for indefinite periods of time, temporary or permanent layoffs, disruptions in supply chains, and lack of availability of certain goods. The impact of such responses could adversely affect the information technology and operational systems upon which the Fund and the Fund’s service providers rely, and could otherwise disrupt the ability of the employees of the Fund’s service providers to perform critical tasks relating to the Fund. Any such impact could adversely affect the Fund’s performance, or the performance of the securities in which the Fund invests and may lead to losses on your investment in the Fund. Cybersecurity Risk. With the increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cybersecurity failures by or breaches of the Fund’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which the Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its net asset value, interfere with Fund shareholders’ ability to transact business or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. Geopolitical Risk . The increasing interconnectivity between global economies and markets increases the likelihood that events or conditions in one country, region, sector, industry or market or with respect to one company may adversely impact issuers in a different country, region, sector, industry or market. For example, adverse developments in the banking or financial services sector could impact companies operating in various sectors or industries and adversely impact the Fund’s investments. Securities in a Fund’s portfolio may underperform due to inflation (or expectations for inflation), interest rates, global demand for particular products or resources, natural disasters, health emergencies (such as epidemics and pandemics), terrorism, regulatory events and governmental or quasi-governmental actions. The occurrence of global events similar to those in recent years, such as terrorist attacks around the world, natural disasters, health emergencies, social and political discord, war or debt crises and downgrades, among others, may result in market volatility and may have long term effects on both the U.S. and global financial markets. Other financial, economic and other global market and social developments or disruptions may result in similar adverse circumstances, and it is difficult to predict when similar events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). Such global events may negatively impact broad segments of businesses and populations, cause a significant negative impact on the performance of the Fund’s investments, adversely affect and increase the volatility of the Fund’s share price, exacerbate preexisting political, social and economic risks to the Fund. The Fund’s operations may be interrupted and any such event(s) could have a significant adverse impact on the value and risk profile of the Fund’s portfolio. There is a risk that you may lose money by investing in the Fund. Market Disruption. Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may continue to result in market volatility and may have long-term effects on the United States and worldwide financial markets and may cause further economic uncertainties in the United States and worldwide. The Fund cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the Common Shares. Anti-Takeover Provisions . The Fund’s Agreement and Declaration of Trust (the “Declaration of Trust”) and Amended and Restated By-Laws (the “By-Laws” and together with the Declaration of Trust) include provisions that could have the effect of limiting the ability of other persons or entities to acquire control of the Fund or to change the composition of its Board. For example, pursuant to the Fund’s Declaration of Trust, the Fund Board is divided into three classes of Trustees with each class serving for a three-year term and certain types of transactions require the favorable vote of holders of at least 75% of the outstanding shares of the Fund. General Fund Investing Risk. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | |||||||||
| Share Price [Table Text Block] | The following table sets forth for each of the periods indicated the high and low closing market prices for the common shares on the New York Stock Exchange, and the corresponding NAV per share and the premium or discount to NAV per share at which the Fund’s common shares were trading as of such date. Market Price ($) NAV per Share on NAV Premium/(Discount) on Fiscal Quarter Ended High Low High Low High Low December 31, 2023 12.65 11.09 13.26 12.20 (4.60) (9.10) September 30, 2023 13.35 11.89 13.41 12.49 (0.45) (4.80) June 30, 2023 12.80 12.06 12.77 12.68 0.23 (4.89) March 31, 2023 13.40 12.09 12.70 12.01 5.51 0.67 December 31, 2022 14.40 11.88 12.26 11.90 17.46 (0.17) September 30, 2022 15.70 12.98 13.76 11.91 14.10 8.98 June 30, 2022 15.77 13.05 15.06 12.41 4.71 5.16 March 31, 2022 16.80 14.77 16.24 14.66 3.45 0.75 | |||||||||
| Market Discount Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Market Discount Risk. As with any security, the market value of the common shares may increase or decrease from the amount initially paid for the common shares. The Fund’s common shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Fund’s NAV may decrease. | |||||||||
| Investment and Market Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Investment and Market Risk. An investment in common shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in common shares represents an indirect investment in the securities owned by the Fund, which are generally traded on a securities exchange or in the over-the-counter markets. The value of these securities, like other market investments, may move up or down, sometimes rapidly and unpredictably. Because the Fund intends to sell index call options on a continuous basis on at least 80% of the value of its total assets, the Fund’s appreciation potential from equity market performance will be limited. The common shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. | |||||||||
| Issuer Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Issuer Risk. The value of securities held by the Fund may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. | |||||||||
| Equity Securities Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Fund’s equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels. | |||||||||
| Option Strategy Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Option Strategy Risk. The Fund’s option strategy seeks to take advantage of, and its effectiveness is dependent on, a general excess of option price implied volatilities for the S&P 500® and NASDAQ 100® indices over realized index volatilities. This market observation is often attributed to an excess of natural buyers over natural sellers of S&P 500® and NASDAQ 100® index options. There can be no assurance that this imbalance will apply in the future over specific periods or generally. It is possible that the imbalance could decrease or be eliminated by actions of investors, including the Fund, that employ strategies seeking to take advantage of the imbalance, which could have an adverse effect on the Fund’s ability to achieve its investment objective. | |||||||||
| Risk of Selling Index Call Options [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risk of Selling Index Call Options. The purchaser of an index call option has the right to any appreciation in the value of the index over the exercise price of the call option as of the valuation date of the option. Because their exercise is settled in cash, sellers of index call options such as the Fund cannot provide in advance for their potential settlement obligations by acquiring and holding the underlying securities. The Fund intends to mitigate the risks of its options activities by holding a diversified portfolio of stocks that the Fund’s investment adviser believes collectively approximate the characteristics of the indices on which options are written. The Fund will not, however, hold stocks that fully replicate the indices on which it writes call options. Due to tax considerations, the Fund intends to limit the overlap between its stock holdings (and any subset thereof) and each index on which it has outstanding options positions to less than 70% on an ongoing basis. The Fund’s stock holdings will normally include stocks not included in the index on which it writes call options. Consequently, the Fund bears the risk that the performance of its stock portfolio will vary from the performance of the indices on which it writes call options. As the writer of index call options, the Fund will forgo, during the option’s life, the opportunity to profit from increases in the value of the applicable index above the sum of the option premium received and the exercise price of the call option, but retains the risk of loss, minus the option premium received, should the value of the applicable index decline. When a call option is exercised, the Fund will be required to deliver an amount of cash determined by the excess of the value of the applicable index at contract termination over the exercise price of the option. Thus, the exercise of index call options sold by the Fund may require the Fund to sell portfolio securities to generate cash at inopportune times or for unattractive prices. The trading price of options may be adversely affected if the market for such options becomes less liquid or smaller. The Fund may close out a call option by buying the option instead of letting it expire or be exercised. There can be no assurance that a liquid market will exist when the Fund seeks to close out a call option position by buying the option. The trading price of options may be adversely affected if the market for such options becomes less liquid or smaller. The Fund may close out a call option by buying the option instead of letting it expire or be exercised. There can be no assurance that a liquid market will exist when the Fund seeks to close out a call option position by buying the option. | |||||||||
| Derivatives Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Derivatives Risk. The Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment. | |||||||||
| TaxSensitive Investing Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Tax-Sensitive Investing Risk. The Fund may hold a security in order to achieve more favorable tax-treatment or to sell a security in order to create tax losses. The Fund’s utilization of various tax-management techniques may be curtailed or eliminated by tax legislation, regulation or interpretations. The Fund may not be able to minimize taxable distributions to shareholders and a portion of the Fund’s distributions may be taxable. | |||||||||
| Tax Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Tax Risk. Although the Fund seeks to minimize and defer the federal income taxes incurred by common shareholders in connection with their investment in the Fund, there can be no assurance that it will be successful in this regard. Market conditions may limit the Fund’s ability to generate tax losses or to generate income taxed at favorable tax rates. The Fund’s tax-managed strategy may cause the Fund to hold a security in order to achieve more favorable tax-treatment or to sell a security in order to create tax losses. The Fund’s ability to utilize various tax-management techniques may be curtailed or eliminated in the future by tax legislation, regulation or interpretations. Distributions paid on the Common Shares may be characterized variously as net investment income (taxable at ordinary income rates), qualified dividends and capital gains dividends (each taxable at long-term capital gains rates) or return of capital (not currently taxable). The ultimate tax characterization of the Fund’s distributions made in a calendar year may not finally be determined until after the end of that calendar year. Distributions to a common shareholder that are a return of capital will be tax free up to the amount of the common shareholder’s current tax basis in his or her Common Shares, with any distribution amounts exceeding such basis treated as capital gain on a deemed sale of Common Shares. common shareholders are required to reduce their tax basis (not below zero) in Common Shares by the amount of tax-free return of capital distributions received, thereby increasing the amount of capital gain (or decreasing the amount of capital loss) to be recognized upon a later disposition of the Common Shares. In order for Fund distributions of qualified dividend income to be taxable at favorable long-term capital gains rates, the Fund must meet certain holding period and other requirements with respect to the dividend-paying stock in its portfolio, and a common shareholder must meet certain prescribed holding period and other requirements with respect to his or her Common Shares. If positions held by the Fund were treated as “straddles” for federal income tax purposes, dividends on such positions would not constitute qualified dividend income subject to favorable income tax treatment. Gain or loss on positions in a straddle are subject to special (and generally disadvantageous) rule. | |||||||||
| Foreign Investment Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund’s investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States, and as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country. Depositary receipts are subject to many of the risks associated with investing directly in foreign instruments, including the political and economic risks of the underlying issuer’s country and, in the case of depositary receipts traded on foreign markets, currency risk. | |||||||||
| Emerging Markets Investment Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain economic sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets. | |||||||||
| Currency Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks. | |||||||||
| Liquidity Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress. | |||||||||
| 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 investments will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the Common Shares and distributions thereon can decline. | |||||||||
| Dividend Capture Trading Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Dividend Capture Trading Risk. The use of dividend capture strategies will expose the Fund to higher portfolio turnover, increased trading costs and potential for capital loss or gain, particularly in the event of significant short-term price movements of stocks subject to dividend capture trading. | |||||||||
| Risk of Investing in Smaller and MidSized Companies [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risk of Investing in Smaller and Mid-Sized Companies. The Fund may make investments in stocks of companies whose market capitalization is considered middle sized or “mid-cap.” Smaller and mid-sized companies often are newer or less established companies than larger companies. Investments in smaller and mid-sized companies carry additional risks because earnings of these companies tend to be less predictable; they often have limited product lines, markets, distribution channels or financial resources; and the management of such companies may be dependent upon one or a few key people. The market movements of equity securities of smaller and mid-sized companies may be more abrupt or erratic than the market movements of equity securities of larger, more established companies or the stock market in general. Historically, smaller and mid-sized companies have sometimes gone through extended periods when they did not perform as well as larger companies. In addition, equity securities of smaller and mid-sized companies generally are less liquid than those of larger companies. This means that the Fund could have greater difficulty selling such securities at the time and price that the Fund would like. | |||||||||
| Technology Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Technology Risk. The technology industries can be significantly affected by obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants and general economic conditions. | |||||||||
| Risks of Growth Stock Investing [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risks of “Growth” Stock Investing. The Fund invests substantially in stocks with “growth” characteristics. Growth stocks can react differently to issuer, political, market and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, growth stocks tend to be sensitive to changes in their earnings and more volatile than other types of stocks. | |||||||||
| Leverage Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Leverage Risk. Certain Fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to an underlying reference instrument. Leverage can also result from borrowings or issuance of preferred shares. Leverage can increase both the risk and return potential of the Fund. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations. Leverage may cause the Fund’s NAV to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the Fund’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment. | |||||||||
| Risks Associated with Active Management [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns. | |||||||||
| Recent Market Conditions [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Recent Market Conditions. The outbreak of COVID-19 and efforts to contain its spread resulted in closing borders, enhanced health screenings, changes to healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this coronavirus and the effects of other infectious illness outbreaks, epidemics or pandemics may be short term or may continue for an extended period of time. Health crises caused by outbreaks of disease, such as the coronavirus outbreak, may exacerbate other pre-existing political, social and economic risks and disrupt normal market conditions and operations. For example, a global pandemic or other widespread health crisis could cause substantial market volatility and exchange trading suspensions and closures. In addition, the increasing interconnectedness of markets around the world may result in many markets being affected by events or conditions in a single country or region or events affecting a single or small number of issuers. The coronavirus outbreak and public and private sector responses thereto have led to large portions of the populations of many countries working from home for indefinite periods of time, temporary or permanent layoffs, disruptions in supply chains, and lack of availability of certain goods. The impact of such responses could adversely affect the information technology and operational systems upon which the Fund and the Fund’s service providers rely, and could otherwise disrupt the ability of the employees of the Fund’s service providers to perform critical tasks relating to the Fund. Any such impact could adversely affect the Fund’s performance, or the performance of the securities in which the Fund invests and may lead to losses on your investment in the Fund. | |||||||||
| Cybersecurity Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Cybersecurity Risk. With the increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. In general, cyber incidents can result from deliberate attacks or unintentional events. Cybersecurity failures by or breaches of the Fund’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which the Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its net asset value, interfere with Fund shareholders’ ability to transact business or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. | |||||||||
| Geopolitical Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Geopolitical Risk . The increasing interconnectivity between global economies and markets increases the likelihood that events or conditions in one country, region, sector, industry or market or with respect to one company may adversely impact issuers in a different country, region, sector, industry or market. For example, adverse developments in the banking or financial services sector could impact companies operating in various sectors or industries and adversely impact the Fund’s investments. Securities in a Fund’s portfolio may underperform due to inflation (or expectations for inflation), interest rates, global demand for particular products or resources, natural disasters, health emergencies (such as epidemics and pandemics), terrorism, regulatory events and governmental or quasi-governmental actions. The occurrence of global events similar to those in recent years, such as terrorist attacks around the world, natural disasters, health emergencies, social and political discord, war or debt crises and downgrades, among others, may result in market volatility and may have long term effects on both the U.S. and global financial markets. Other financial, economic and other global market and social developments or disruptions may result in similar adverse circumstances, and it is difficult to predict when similar events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). Such global events may negatively impact broad segments of businesses and populations, cause a significant negative impact on the performance of the Fund’s investments, adversely affect and increase the volatility of the Fund’s share price, exacerbate preexisting political, social and economic risks to the Fund. The Fund’s operations may be interrupted and any such event(s) could have a significant adverse impact on the value and risk profile of the Fund’s portfolio. There is a risk that you may lose money by investing in the Fund. | |||||||||
| Market Disruption [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Market Disruption. Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may continue to result in market volatility and may have long-term effects on the United States and worldwide financial markets and may cause further economic uncertainties in the United States and worldwide. The Fund cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the Common Shares. | |||||||||
| AntiTakeover Provisions [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Anti-Takeover Provisions . The Fund’s Agreement and Declaration of Trust (the “Declaration of Trust”) and Amended and Restated By-Laws (the “By-Laws” and together with the Declaration of Trust) include provisions that could have the effect of limiting the ability of other persons or entities to acquire control of the Fund or to change the composition of its Board. For example, pursuant to the Fund’s Declaration of Trust, the Fund Board is divided into three classes of Trustees with each class serving for a three-year term and certain types of transactions require the favorable vote of holders of at least 75% of the outstanding shares of the Fund. | |||||||||
| General Fund Investing Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | General Fund Investing Risk. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | |||||||||
| Interest Rate Risk [Member] | ||||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Risk [Text Block] | Interest Rate Risk. The premiums from writing index call options and amounts available for distribution from the Fund’s options activity may decrease in declining interest rate environments. The value of the Fund’s common stock investments may also be influenced by changes in interest rates. Higher yielding stocks and stocks of issuers whose businesses are substantially affected by changes in interest rates may be particularly sensitive to interest rate risk. | |||||||||
| Common Shares [Member] | ||||||||||
| Other Annual Expenses [Abstract] | ||||||||||
| Basis of Transaction Fees, Note [Text Block] | Percentage of net assets | |||||||||
| General Description of Registrant [Abstract] | ||||||||||
| Lowest Price or Bid | $ 11.09 | $ 11.89 | $ 12.06 | $ 12.09 | $ 11.88 | $ 12.98 | $ 13.05 | $ 14.77 | ||
| Highest Price or Bid | 12.65 | 13.35 | 12.8 | 13.4 | 14.4 | 15.7 | 15.77 | 16.8 | ||
| Lowest Price or Bid, NAV | 12.2 | 12.49 | 12.68 | 12.01 | 11.9 | 11.91 | 12.41 | 14.66 | ||
| Highest Price or Bid, NAV | $ 13.26 | $ 13.41 | $ 12.77 | $ 12.7 | $ 12.26 | $ 13.76 | $ 15.06 | $ 16.24 | ||
| Highest Price or Bid, Premium (Discount) to NAV [Percent] | (4.60%) | (0.45%) | 0.23% | 5.51% | 17.46% | 14.10% | 4.71% | 3.45% | ||
| Lowest Price or Bid, Premium (Discount) to NAV [Percent] | (9.10%) | (4.80%) | (4.89%) | 0.67% | (0.17%) | 8.98% | 5.16% | 0.75% | ||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | ||||||||||
| Outstanding Security, Title [Text Block] | Common Shares | |||||||||
| Outstanding Security, Held [Shares] | 116,754,568 | |||||||||
| [1]If common shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load.[2]You will be charged a $5.00 service charge and pay brokerage charges if you direct the plan agent to sell your common shares held in a dividend reinvestment account.[3]Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering.[4]Stated as a percentage of average net assets attributable to common shares for the year ended December 31, 2023.[5]The investment adviser fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. | ||||||||||