rr_AverageAnnualReturnYear01

13.26%

rr_AverageAnnualReturnSinceInception

(10.76%)

rr_AverageAnnualReturnYear01

12.10%

rr_AverageAnnualReturnSinceInception

(11.27%)

Risk Return Abstract

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rr_AverageAnnualReturnYear05

2.53%

rr_AverageAnnualReturnLabel

(reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnYear05

4.53%

rr_AverageAnnualReturnLabel

(reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnYear05

12.18%

rr_AverageAnnualReturnLabel

(reflects no deduction for fees, expenses or taxes)

Objective, Primary [Text Block]

rr_AverageAnnualReturnYear05

7.59%

Risk/Return [Heading]

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Summary Information

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The First Trust Global Engineering and Construction ETF (the "Fund"), formerly First Trust ISE Global Engineering and Construction Index Fund, seeks investment results that correspond generally to the price and yield (before the Fund's fees and expenses) of an equity index called the ISE Global Engineering and Construction(TM) Index (the "Index").

Expense Narrative [Text Block]

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The following table describes the fees and expenses you may pay if you buy and hold shares of the Fund. Investors purchasing and selling shares may be subject to costs (including customary brokerage commissions) charged by their broker, which are not reflected in the table below.

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 46% of the average value of its portfolio.

Expense Example, No Redemption Narrative [Text Block]

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The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. This example does not take into account customary brokerage commissions that you pay when purchasing or selling shares of the Fund in the secondary market.

The example assumes that you invest $10,000 in the Fund for the time periods indicated. The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain at current levels until January 31, 2017, and thereafter at 1.24% to represent the imposition of the 12b-1 fee of 0.25% per annum of the Fund's average daily net assets. The example assumes that First Trust's agreement to waive fees and/or pay the Fund's expenses to the extent necessary to prevent the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes, and extraordinary expenses) from exceeding 0.70% of average daily net assets per year will be terminated following January 31, 2017. 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 will normally invest at least 90% of its net assets (including investment borrowings) in common stocks or in depositary receipts representing securities in the Index. The Fund's investment advisor seeks to match the performance of the Index (before the Fund's fees and expenses).

The Fund, using an indexing investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Fund's investment advisor seeks a correlation of 0.95 or better (before fees and expenses) between the Fund's performance and the performance of the Index; a figure of 1.00 would represent perfect correlation.

The Index is owned and was developed by the International Securities Exchange, LLC(R) ("ISE" or "Index Provider"). The Index Provider has contracted with Standard & Poor's Dow Jones Indices to calculate and maintain the Index. The Index provides a benchmark for investors interested in tracking public companies throughout the world that are active in the engineering and construction industries, based on analysis of the products and services offered by those companies. The Index specifically targets companies that are engaged in large civil and capital projects such as infrastructure, utilities, transportation, telecommunications, commercial, residential, and commerce facilities and whose roles are within the engineering, designing, planning, consulting, project managing, and/or constructing of these projects. To be included in the Index, a company must receive at least 70% of revenues from these types of services and projects based on the reportable segment/division from its most recent annual report. As of September 30, 2015, the Index had significant investments in industrials companies.

The Fund intends to invest entirely in securities included in the Index; however, there may also be instances in which the Fund may be underweighted or overweighted in certain securities in the Index, not invest in certain securities included in the Index, purchase securities not in the Index that are appropriate to substitute for certain securities in the Index or utilize various combinations of the above techniques in seeking to track the Index.

Risk Narrative [Text Block]

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You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund's investment objective will be achieved.

CURRENCY RISK. The Fund may hold investments that are denominated in non-U.S. currencies, or in securities that provide exposure to such currencies, currency exchange rates or interest rates denominated in such currencies. Changes in currency exchange rates and the relative value of non-U.S. currencies will affect the value of the Fund's investment and the value of Fund shares. Currency exchange rates can be very volatile and can change quickly and unpredictably. As a result, the value of an investment in the Fund may change quickly and without warning and you may lose money.

DEPOSITARY RECEIPTS RISK. Depositary receipts may be less liquid than the underlying shares in their primary trading market. Any distributions paid to the holders of depositary receipts are usually subject to a fee charged by the depositary. Holders of depositary receipts may have limited voting rights, and investment restrictions in certain countries may adversely impact the value of depositary receipts because such restrictions may limit the ability to convert the equity shares into depositary receipts and vice versa. Such restrictions may cause the equity shares of the underlying issuer to trade at a discount or premium to the market price of the depositary receipts.

ENGINEERING AND CONSTRUCTION COMPANIES RISK. Risks associated with investing in engineering and construction companies include the general state of the economy, demand for their specific products or services, changes in government spending, zoning laws, interest rates, declines in real estate values, environmental damage and product liability claims. In addition, they may also be significantly affected by overall capital spending levels, economic cycles, technical obsolescence, delays in modernization, labor relations, government regulations and e-commerce initiatives.

EQUITY SECURITIES RISK. Because the Fund invests in equity securities, the value of the Fund's shares will fluctuate with changes in the value of these equity securities. Equity securities prices fluctuate for several reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant stock market, such as market volatility, or when political or economic events affecting the issuers occur. In addition, common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.

INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Some industrials companies are involved in electrical equipment and components, industrial products, manufactured housing and telecommunications equipment. General risks of industrials companies include the general state of the economy, intense competition, consolidation, domestic and international politics, excess capacity and consumer demand and spending trends. In addition, they may also be significantly affected by overall capital spending levels, economic cycles, technical obsolescence, delays in modernization, labor relations, government regulations and e-commerce initiatives.

JAPAN RISK. Because Japan's economy and equity market share a strong correlation with the U.S. markets, the Japanese economy may be affected by economic problems in the U.S. Japan also has a growing economic relationship with China and other Southeast Asian countries, and thus Japan's economy may also be affected by economic, political or social instability in those countries. Despite a strengthening in the economic relationship between Japan and China, the countries' political relationship has at times been strained in recent years. Should political tension increase, it could adversely affect the economy and destabilize the region as a whole. Japan also remains heavily dependent on oil imports, and higher commodity prices could therefore have a negative impact on the economy. Japanese securities may also be subject to lack of liquidity; excessive taxation; government seizure of assets; different legal or accounting standards and less government supervision and regulation of exchanges than in the United States. Furthermore, the natural disasters that have impacted Japan and the ongoing recovery efforts have had a negative affect on Japan's economy, and may continue to do so.

MARKET RISK. Market risk is the risk that a particular security owned by the Fund or shares of the Fund in general may fall in value. Securities are subject to market fluctuations caused by such factors as economic, political, regulatory or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments.

NON-CORRELATION RISK. The Fund's return may not match the return of the Index for a number of reasons. For example, the Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund's portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund's portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index.

NON-U.S. SECURITIES RISK. Non-U.S. securities are subject to higher volatility than securities of domestic issuers due to possible adverse political, social or economic developments; restrictions on foreign investment or exchange of securities; lack of liquidity; currency exchange rates; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries.

REPLICATION MANAGEMENT RISK. The Fund is exposed to additional market risk due to its policy of investing principally in the securities included in the Index. As a result of this policy, securities held by the Fund will generally not be bought or sold in response to market fluctuations.

SMALL FUND RISK. The Fund currently has fewer assets than larger funds, and like other relatively smaller funds, large inflows and outflows may impact the Fund's market exposure for limited periods of time. This impact may be positive or negative, depending on the direction of market movement during the period affected. Also, during the initial invest-up period, the Fund may depart from its principal investment strategies and invest a larger amount or all of its assets in cash equivalents or it may hold cash.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

Performance Narrative [Text Block]

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The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year-to-year and by showing how the Fund's average annual total returns based on net asset value compare to those of the Index, a broad-based market index and a specialized market index. See "Total Return Information" for additional performance information regarding the Fund. The Fund's performance information is accessible on the Fund's website at www.ftportfolios.com.

Returns before taxes do not reflect the effects of any income or capital gains taxes. All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for the market indices do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Bar Chart Footnotes [Text Block]

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During the periods shown in the chart above:

Best Quarter		Worst Quarter
28.36%	June 30, 2009	-24.67%	September 30, 2011

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of Offering Price)

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none

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

^[1]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.99%

Total Net Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement

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0.70%

3 Years

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340

Expense Example, No Redemption, 10 Years

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$ 1,452

Annual Return 2010

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18.23%

Annual Return 2012

rr_AnnualReturn2012

19.21%

Annual Return 2014

rr_AnnualReturn2014

(10.66%)

rr_AverageAnnualReturnYear01

(0.59%)

rr_AverageAnnualReturnSinceInception

7.13%

rr_AverageAnnualReturnYear01

(1.06%)

rr_AverageAnnualReturnSinceInception

6.51%

Risk Return Abstract

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rr_AverageAnnualReturnYear05

0.86%

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(reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnYear05

2.76%

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(reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnYear05

12.18%

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(reflects no deduction for fees, expenses or taxes)