Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).

Expense Example Narrative [Text Block]

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This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Strategy Narrative [Text Block]

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The Fund seeks to achieve its investment objective by investing in exchange-traded futures contracts on the Bloomberg Roll Select Commodity Index (the “Index Futures”). The Fund is expected to roll out of existing positions in Index Futures and establish new positions in Index Futures on an ongoing basis. Index Futures subsequently acquired by the Fund may have terms that differ from those of the Index Futures it currently holds and the purchase and sale of these Index Futures may incur transaction fees. In seeking total return, the Fund also seeks to generate interest income and capital appreciation on the cash balances arising from its investment in Index Futures through a cash management strategy consisting of investments in cash and cash equivalents, short-term government obligations and short-term investment-grade fixed-income securities (collectively, “Fixed-Income Investments”).

The Fund is an actively managed exchange-traded fund (“ETF”) and does not seek to replicate the performance of a specified index. While the Fund is not an index fund, the Fund’s investment strategy seeks to maximize correlation with the Bloomberg Roll Select Commodity Index (the “Bloomberg Benchmark”), which is composed of 22 futures contracts across 20 physical agricultural, energy, precious metals and industrial metals commodities. The Bloomberg Benchmark reflects the returns from these commodity futures contracts, and provides broad-based exposure to commodities as an asset class by using liquidity factors and sector caps to avoid over-concentration in any single commodity or commodity sector. In order to maintain exposure to a futures contract on a particular commodity, an investor must sell the position in the expiring contract and buy a new position in a contract with a later delivery month, which is referred to as “rolling.” If the price for the new futures contract is less than the price of the expiring contract, then the market for the commodity is said to be in “backwardation.” In these markets, roll returns are positive, which is referred to as “positive carry.” The term “contango” is used to describe a market in which the price for a new futures contract is more than the price of the expiring contract. In these markets, roll returns are negative, which is referred to as “negative carry.” The Bloomberg Benchmark seeks to employ a positive carry strategy that emphasizes commodities and futures contract months with the greatest degree of backwardation and lowest degree of contango, resulting in net gains through positive roll returns.

The Fund will invest in financial instruments providing exposure to commodities and not in the physical commodities themselves. The Fund may also invest in exchange-traded commodity futures contracts similar to those found in the Bloomberg Benchmark, as well as swaps and options on futures that correlate to the investment returns of commodities without investing directly in physical commodities and over-the-counter commodity-linked instruments like commodity-linked notes, swaps and forward contracts (together, the “Commodity Investments”). Investing in derivative contracts may have a leveraging effect on the Fund. Although the Fund may hold the same futures contracts under the same futures rolling schedule as those included in the Bloomberg Benchmark, the Fund is not obligated to invest in any futures contracts included in, and does not seek to replicate the performance of, the Bloomberg Benchmark.

The Fund seeks to gain exposure to Index Futures and other Commodity Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary invests solely in Commodity Investments and cash and cash equivalents. In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Commodity Investments held in the Subsidiary are intended to provide the Fund with exposure to broad commodities consistent with current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in Commodity Investments.

The remainder of the Fund’s assets will be invested directly by the Fund, primarily in Fixed-Income Investments, including repurchase agreements, money market instruments, U.S. government and agency securities, Treasury inflation-protected securities, sovereign debt obligations on non-U.S. countries and investment-grade corporate bonds. The Fund invests in Fixed-Income Investments for investment purposes and to provide sufficient assets to account for (or “cover”) mark-to-market changes and to collateralize the Subsidiary’s investments in derivatives.

The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund’s potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).

Risk Narrative [Text Block]

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As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF. The order of the below risk factors does not indicate the significance of any particular risk factor.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market).

Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of the Prospectus), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Carry Strategy Risk. The futures market for a commodity in which the price for a new futures contract is less than the price of an expiring contract, known as a market trading in a state of “backwardation,” may not continue to trade with the same degree of backwardation or with the resulting returns. To the extent that a commodity futures market is not trading in a state of backwardation (or is trading in such a state, but to a lesser degree), the Fund’s cost to maintain exposure to the commodity may increase, the positive carry strategy may prove unsuccessful, and the investment performance of the Fund may suffer.

Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments.

Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. Spot prices and futures prices for commodities will vary depending upon expectations regarding market conditions. Both spot and futures prices of commodity-linked investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio because of the leverage inherent in the use of derivatives. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund.

Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund and the Subsidiary under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time.

Commodity Risk. The Fund has substantial exposure to commodities. The Fund invests in instruments and companies that are susceptible to fluctuations in certain commodity markets and to price changes due to trade relations, including the imposition of tariffs by the U.S. and other countries. Any negative changes in commodity markets that may be due to changes in supply and demand for commodities, market events, regulatory developments or other factors that the Fund cannot control could have an adverse impact on the Commodity Investments in which the Fund invests.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Counterparty Risk. Certain commodity-linked derivative instruments, uncleared swaps and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all and, if the counterparty is subject to specified types of resolution proceedings, the Fund may be subject to stays that limit its ability to close out positions and limit risk. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cybersecurity Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers, market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions, negatively impact the Fund’s business operations and/or potentially result in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cybersecurity plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

Energy Sector Risk. The performance of energy-related commodities is generally cyclical and highly dependent on energy prices. The market value of energy-related commodities may decline for many reasons, including, among others, changes in energy prices, energy supply and demand, global political changes, terrorism, natural disasters and other catastrophes; government regulations, taxation policies and energy conservation efforts.

Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund is exposed to rolling futures contracts, it may be subject to additional risk. In addition, CFTC regulations limit the types of foreign listed futures contracts that U.S. investors, like the Fund, are allowed to invest in. As a result, the Fund may not be able to gain the exposure it seeks through certain non-U.S. futures contracts.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. During periods of market volatility, liquidity in the market for the Fund’s shares may be impacted by the liquidity in the market for the underlying securities or instruments held by the Fund, which could lead to the Fund’s shares trading at a premium or discount to the Fund’s NAV.

Income Risk. The Fund’s income may decline when yields fall. This decline can occur because the Fund may subsequently invest in lower-yielding Fixed-Income Investments, as Fixed-Income Investments in its portfolio mature, are near maturity or are called, or the Fund otherwise needs to purchase additional bonds.

Infectious Illness Risk. An outbreak of an infectious respiratory illness, COVID-19, caused by a novel coronavirus has resulted in travel restrictions, disruption of healthcare systems, prolonged quarantines, cancellations, supply chain disruptions, lower consumer demand, layoffs, ratings downgrades, defaults and other significant economic impacts. Certain markets have experienced temporary closures, extreme volatility, severe losses, reduced liquidity and increased trading costs. These events will have an impact on the Fund and its investments and could impact the Fund’s ability to purchase or sell securities or cause elevated tracking error and increased premiums or discounts to the Fund’s NAV. Other infectious illness outbreaks in the future may result in similar impacts.

Interest Rate Risk. During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns or pay dividends to Fund shareholders. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, result in heightened market volatility and detract from the Fund’s performance to the extent the Fund is exposed to such interest rates. Additionally, under certain market conditions in which interest rates are low and the market prices for portfolio securities have increased, the Fund may have a very low, or even negative yield. A low or negative yield would cause the Fund to lose money in certain conditions and over certain time periods. An increase in interest rates will generally cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments, including those held by the Fund. The historically low interest rate environment heightens the risks associated with rising interest rates.

Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure as well as the correlation among the assets.The Fund may be adversely affected if an issuer of underlying securities held by the Fund is unable or unwilling to repay principal or interest when due. Changes in the financial condition or credit rating of an issuer of those securities or of securities referenced by swaps or other derivatives or the seller or counterparty with respect to derivatives or other assets may cause the value of the securities, derivatives, or other assets to decline.

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities or assets selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issue, recessions, or other events could have a significant impact on the Fund and its investments and could result in increased premiums or discounts to the Fund’s NAV.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price.

Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers or in derivatives with a limited number of counterparties. As a result, the Fund's performance may depend on the performance of a small number of issuers and counterparties.

Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Risk of Investing in Agriculture and Livestock. Investments in the agricultural and livestock sectors may be volatile and change unpredictably as a result of many factors, such as legislative or regulatory developments relating to food safety, the imposition of tariffs or other trade restraints, and the supply and demand of each commodity. Increased competition and changes in consumer tastes and spending can also influence the demand for agricultural and livestock products, affecting the price of such commodities and the performance of the Fund.

Risk of Investing in Developed Countries. The Fund’s investment in developed country issuers may subject the Fund to regulatory, political, currency, security, economic and other risks associated with developed countries. Developed countries tend to represent a significant portion of the global economy and have generally experienced slower economic growth than some less developed countries. Certain developed countries have experienced security concerns, such as terrorism and strained international relations. Incidents involving a country’s or region’s security may cause uncertainty in its markets and may adversely affect its economy and the Fund’s investments. In addition, developed countries may be adversely impacted by changes to the economic conditions of certain key trading partners, regulatory burdens, debt burdens and the price or availability of certain commodities.

Risk of Investing in Industrial Metals. The industrial metals sector may be adversely affected by changes in international economic and political conditions, increased competition and changes in industrial and commercial demand for industrial metals. As a result, the price of industrial metals has been subject to substantial price fluctuations over short periods of time.

Risk of Investing in Precious Metals. Prices of precious metals and of precious metal-related financial instruments historically have been very volatile. The high volatility of precious metal prices may adversely affect the prices of financial instruments that derive their value from the price of underlying precious metals. The production and sale of precious metals by governments or central banks or other larger holders can be affected by various economic, financial, social and political factors, which may be unpredictable and may have a significant impact on the prices of precious metals.

Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure.

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Certain standardized interest rate and credit default swaps are required to be traded on an exchange or trading platform and centrally cleared. Most other swaps are entered into a negotiated, bi-lateral basis and traded in the over-the-counter market. Swaps are subject to bi-lateral variation margin. Initial margin requirements are in the process of being phased in, and the Fund may be subject to such requirements as early as September 2020.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Any resulting liquidation of the Fund could cause the Fund to incur elevated transaction costs for the Fund and negative tax consequences for its shareholders.

Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund.

Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. Based on final regulations issued by the U.S. Internal Revenue Service (“IRS”) on which taxpayers may rely for taxable years beginning after September 28, 2016, the Fund expects its income with respect to the Subsidiary to be qualifying income. In the future, if the IRS issues new regulations or other guidance, or Congress enacts legislation, limiting the circumstances in which the Fund’s income with respect to the Subsidiary will be considered “qualifying income,” the Fund might be required to make changes to its operations, which could reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders could also experience adverse tax consequences in such circumstances.

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

Risk Nondiversified Status [Text]

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Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers or in derivatives with a limited number of counterparties. As a result, the Fund's performance may depend on the performance of a small number of issuers and counterparties.

Performance Narrative [Text Block]

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The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

Performance Availability Phone [Text]

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1-800-iShares (1-800-474-2737) (toll free)

Performance Past Does Not Indicate Future [Text]

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Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

Bar Chart Closing [Text Block]

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The best calendar quarter return during the period shown above was 5.45% in the 1st quarter of 2019; the worst was -2.41% in the 3rd quarter of 2019.

Updated performance information, including the Fund’s current NAV, may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

Performance Table Uses Highest Federal Rate

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After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.

Performance Table Explanation after Tax Higher

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Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

Risk/Return:

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Distribution and Service (12b-1) Fees

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none

Acquired Fund Fees and Expenses

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0.01%

Fee Waiver

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(0.01%)

1 Year