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 22% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. 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 0.60% of average daily net assets per year will be terminated following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

263

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,165

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively, "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index is an indicated annual dividend yield weighted index of 100 stocks selected from the developed-market portion of the Dow Jones World Index(SM). Indicated annual dividend yield is a stock's unadjusted indicated annual dividend (not including any special dividends) divided by its unadjusted price. The Index is compiled and maintained by Dow Jones & Company, Inc. ("Dow Jones" or the "Index Provider"). The Index universe consists of all dividend-paying companies in the Dow Jones World Developed Index which are subjected to eligibility screens for dividend quality and liquidity before being selected for inclusion in the Index. Component securities are weighted on indicated annual dividend yield. Weights of individual securities are capped at 10%. The Index is rebalanced and reconstituted annually in December. The Fund will make changes to its portfolio holdings when changes are made by the Index Provider in the composition of the Index.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

MID-CAP STOCK RISK. The Fund invests in mid-cap company stocks, which may be subject to more abrupt or erratic market movements than those of larger, more established companies or the market averages in general.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

TELECOMMUNICATION SECTOR RISK. The Fund invests in companies in the telecommunication sector. Telecommunication companies are subject to risks, such as: a market characterized by increasing competition and regulation by the Federal Communications Commission and various state regulatory authorities; the need to commit substantial capital to meet increasing competition, particularly in formulating new products and services using new technology; and technological innovations that may make various products and services obsolete.

NON-U.S. SECURITIES RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below illustrate the annual calendar year returns of the Fund based on NAV for the past four years as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. 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 NAV compare to those of the Index and two broad-based securities market indices. 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 Closing [Text Block]

rr_BarChartClosingTextBlock

During the four-year period ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were 38.58% and -29.38%, respectively, for the quarters ended June 30, 2009 and December 31, 2008. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

1 Year

rr_AverageAnnualReturnYear01

(2.39%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 21, 2007

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(3.54%)

1 Year

rr_AverageAnnualReturnYear01

(5.54%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 21, 2007

Risk/Return:

rr_RiskReturnAbstract

Annual Return 2009

rr_AnnualReturn2009

64.28%

Annual Return 2011

rr_AnnualReturn2011

(2.17%)

Since Inception

rr_AverageAnnualReturnSinceInception

(2.65%)

1 Year

rr_AverageAnnualReturnYear01

(3.82%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 21, 2007

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(3.22%)

Risk/Return [Heading]

rr_RiskReturnHeading

SUMMARY INFORMATION

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The First Trust FTSE EPRA/NAREIT Developed Markets Real Estate Index Fund (the "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 FTSE EPRA/NAREIT Developed Index (the "Index").

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

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.

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Management Fees

rr_ManagementFeesOverAssets

0.40%

Other Expenses

rr_OtherExpensesOverAssets

0.46%

Fee Waiver and Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.26%)

^[2]

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

PORTFOLIO TURNOVER

Expense Example [Heading]

rr_ExpenseExampleHeading

EXAMPLE

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

61

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

545

Strategy [Heading]

rr_StrategyHeading

PRINCIPAL INVESTMENT STRATEGIES

Risk [Heading]

rr_RiskHeading

PRINCIPAL RISKS

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

ANNUAL TOTAL RETURN

Bar Chart [Heading]

rr_BarChartHeading

FIRST TRUST FTSE EPRA/NAREIT DEVELOPED MARKETS REAL ESTATE INDEX FUND--TOTAL RETURNS

Performance Table Heading

rr_PerformanceTableHeading

AVERAGE ANNUAL TOTAL RETURNS FOR THE PERIODS ENDED DECEMBER 31, 2011

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(5.37%)

1 Year

rr_AverageAnnualReturnYear01

0.61%

Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 27, 2007

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(5.47%)

Annual Return 2008

rr_AnnualReturn2008

(47.46%)

Annual Return 2010

rr_AnnualReturn2010

19.59%

1 Year

rr_AverageAnnualReturnYear01

(6.49%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 27, 2007

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(7.52%)

1 Year

rr_AverageAnnualReturnYear01

(4.20%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 27, 2007

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

^[1]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.60%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 fiscal period July 5, 2011 (inception) through September 30, 2011, the Fund's portfolio turnover rate was 1% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

237

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,018

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks and depositary receipts included in the Index.

The Fund, using an "indexing" investment approach, attempts to replicate, before fees and expenses, the performance of the Index. First Trust Advisors L.P. ("First Trust"), 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 International Securities Exchange, LLC ("ISE" or the "Index Provider"). The Index Provider has contracted with Standard & Poor's to calculate and maintain the Index. The Index is designed to provide a benchmark for investors interested in tracking companies actively involved in the cloud computing industry. The cloud computing industry is a group of companies that offers internet and technology products, services and applications delivered via the Internet rather than traditional computing, which focuses on computer desktop applications. The Index components are reviewed semi-annually for eligibility. As of December 31, 2011, the Index was comprised of 41 securities from companies located in the United States and 1 security from companies located in each of Germany, India, Israel and Canada.

The Index uses a market capitalization weighted allocation across three categories in the cloud computing industry. The pure play category includes companies that are direct service providers for "the cloud" (i.e., network hardware/software, storage and cloud computing services) or companies with business models that rely on delivering goods and services that utilize cloud computing technology. The non pure play category includes companies that focus outside the cloud computing space but provide goods and services that support the cloud computing space. The technology conglomerate category includes companies that are large, broad-based companies with business models that indirectly utilize or support the use of cloud computing technology.

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]

rr_RiskNarrativeTextBlock

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.

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

MID-CAP STOCK RISK. The Fund invests in mid-cap company stocks, which may be subject to more abrupt or erratic market movements than those of larger, more established companies or the market averages in general.

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.

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. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

CLOUD COMPUTING INDUSTRY RISK. The Fund invests in securities of companies engaged in the cloud computing industry, including companies that provide remote computation, software, data access and storage services. The risks related to investing in such companies include disruption in service caused by hardware or software failure, interruptions or delays in service by third-party data center hosting facilities and maintenance providers, security breaches involving certain private, sensitive, proprietary and confidential information managed and transmitted by cloud computing companies, and privacy concerns and laws, evolving Internet regulation and other foreign or domestic regulations that may limit or otherwise affect the operations of such companies. Also, the business models employed by the companies in the cloud computing industry may not prove to be successful.

INFORMATION TECHNOLOGY COMPANIES RISK. The Fund invests in the securities of information technology companies. Information technology companies are generally subject to the risks of rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. Information technology companies may be smaller and less experienced companies, with limited product lines, markets or financial resources and fewer experienced management or marketing personnel. Information technology company stocks, particularly those involved with the Internet, have experienced extreme price and volume fluctuations that often have been unrelated to their operating performance.

INTERNET COMPANIES RISK. The Fund invests in the securities of Internet companies. Internet companies are subject to rapid changes in technology, worldwide competition, rapid obsolescence of products and services, loss of patent protections, cyclical market patterns, evolving industry standards, frequent new product introductions and the considerable risk of owning small capitalization companies that have recently begun operations.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The Fund has not yet operated for a full calendar year and, therefore, performance information is not included in this section of the Prospectus. See "Total Return Information" for performance information regarding the Fund.

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

^[1]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.70%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 41% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

269

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,135

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in securities that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively, "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust Advisors L.P. ("First Trust"), 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index is developed and owned by International Securities Exchange, LLC ("ISE" or the "Index Provider"). The Index is designed to provide a benchmark for investors interested in tracking public companies that are active in the copper mining business based on analysis of revenue derived from the sale of copper. Issuers of component securities must be actively engaged in some aspect of the copper mining business such as copper mining, refining or exploration. The Index has been created to provide investors with a product allowing them to quickly take advantage of both event-driven news and long-term trends as the need for copper continues to evolve.

ISE reviews the Index components quarterly in March, June, September and December of each year for eligibility and sets each component's weight in the Index according to the Index methodology. Changes are announced on ISE's publicly available website at www.ise.com at least five days prior to the effective date.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

SMALLER COMPANY RISK. The Fund invests in small and mid capitalization companies. Such 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.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

COPPER MINING COMPANY RISK. Securities in the Fund's portfolio may be significantly impacted by competitive pressures in the copper mining business and the price of copper. Because more than half of the world's copper production occurs in the United States, Chile, Canada, Russia and Zambia, the Fund's Share price may be particularly sensitive to any adverse political or economic developments affecting these countries. The Fund's Share price may experience volatility because the price of copper may fluctuate substantially over short periods of time. Moreover, the Index tracks companies involved in the copper mining business and not the price of copper. The securities of companies involved in the copper mining business may under- or over-perform the price of copper over the short term or the long term.

MATERIALS RISK. The Fund invests significantly in companies involved in the materials sector. General risks of the materials sector include the general state of the economy, consolidation, domestic and international politics and excess capacity. In addition, basic materials companies may also be significantly affected by volatility of commodity prices, import controls, worldwide competition, liability for environmental damage, depletion of resources and mandated expenditures for safety and pollution control devices.

COPPER RISK. The Fund may be adversely affected by a decrease in the worldwide demand and price of copper. Various factors may lead to a decreased demand and price of copper. As an industrial metal, the demand for and price of copper may be negatively impacted by a decreased level of industrial activity using copper. Other factors include the availability of substitutes such as man-made or synthetic substitutes, disruptions in the supply chain, from mining to storage to smelting or refining, adjustments to inventory, variations in production costs, including storage, labor and energy costs, costs associated with regulatory compliance, including environmental regulations and changes in industrial, government and consumer demand, both in individual consuming nations and internationally.

CANADA RISK. Because the Fund invests a significant portion of its assets in companies that are domiciled in Canada, the Fund is particularly sensitive to political, economic and social conditions in that country. Canada is a major producer of metals and energy-related products. The Canadian economy is very dependent on the demand for, and supply and price of, natural resources, and the Canadian market is relatively concentrated in issuers involved in the production and distribution of natural resources. Any adverse events that affect Canada's major industries may have a negative impact on the overall Canadian economy and the Shares of the Fund.

UNITED KINGDOM RISK. Because the Fund invests a significant portion of its assets in companies that are domiciled in the United Kingdom, the Fund is particularly sensitive to political, economic and social conditions in that country. The Fund may be affected unfavorably by political developments, social instability, changes in government policies and other political and economic developments in the United Kingdom.

NON-U.S. SECURITIES AND EMERGING MARKETS RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries. These risks may be heightened for securities of companies located in, or with significant operations in, emerging market countries.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below illustrate the annual calendar year returns of the Fund based on NAV for the past year as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. The bar chart and table provide an indication of the risks of investing in the Fund by showing how the Fund's average annual total returns based on NAV compare to those of the Index and two broad-based securities market indices. 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 Closing [Text Block]

rr_BarChartClosingTextBlock

During the year ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were 15.51% and -37.68%, respectively, for the quarters ended December 31, 2011 and 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.

1 Year

rr_AverageAnnualReturnYear01

(7.35%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

2.99%

1 Year

rr_AverageAnnualReturnYear01

(21.46%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(29.36%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

0.61%

1 Year

rr_AverageAnnualReturnYear01

(19.04%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.80%

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

rr_NetExpensesOverAssets

0.70%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 22% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. 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, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

287

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,240

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively, "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index is developed and owned by the International Securities Exchange, LLC(R) ("ISE" or "Index Provider"), in consultation with Standard & Poor's, a Division of The McGraw-Hill Companies, Inc. ("S&P"), which calculates and maintains 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.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

SMALLER COMPANY RISK. The Fund invests in small and mid capitalization companies. Such 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.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

ENGINEERING AND CONSTRUCTION RISK. The Fund invests in the securities of engineering and construction companies. Risks associated with investing in these 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.

INDUSTRIALS SECTOR RISK. The Fund invests in the securities of companies in the industrials sector. Many companies in this sector convert unfinished goods into finished durables used to manufacture other goods or provide services. Some industries included in this sector are electrical equipment and components, industrial products, manufactured housing and telecommunications equipment. General risks of these 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.

NON-U.S. SECURITIES RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries.

JAPAN RISK. The Fund invests in the stock of companies operating in Japan. 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.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below illustrate the annual calendar year return of the Fund based on NAV for the past three years as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. 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 NAV compare to those of the Index, the Russell 3000(R) Index, which is a broad-based securities market index, and a specialized securities 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 Closing [Text Block]

rr_BarChartClosingTextBlock

During the three-year period ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were 28.36% and -24.67%, respectively, for the quarters ended June 30, 2009 and 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.

1 Year

rr_AverageAnnualReturnYear01

(16.64%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 13, 2008

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

10.23%

1 Year

rr_AverageAnnualReturnYear01

(8.20%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 13, 2008

Risk/Return:

rr_RiskReturnAbstract

Annual Return 2010

rr_AnnualReturn2010

18.23%

1 Year

rr_AverageAnnualReturnYear01

(17.44%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 13, 2008

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

6.96%

1 Year

rr_AverageAnnualReturnYear01

(11.29%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 13, 2008

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

^[1]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.70%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 41% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

269

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,135

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in securities that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively, "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust Advisors L.P. ("First Trust"), 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index is developed and owned by International Securities Exchange, LLC ("ISE" or the "Index Provider"). The Index is designed to provide a benchmark for investors interested in tracking public companies that are active in platinum group metals ("PGM") mining based on revenue analysis of those companies. PGMs collectively refer to six elements, platinum, palladium, osmium, iridium, ruthenium and rhodium, which have similar physical and chemical properties and tend to occur together in the same mineral deposits. Issuers of component securities must be actively engaged in some aspect of PGM mining such as mining, refining or exploration. The Index has been created to provide investors with a product allowing them to quickly take advantage of both event-driven news and long-term trends as the need for PGMs continues to evolve.

ISE reviews the Index components quarterly in March, June, September and December of each year for eligibility and sets each component's weight in the Index according to the Index methodology. Changes are announced on ISE's publicly available website at www.ise.com at least five days prior to the effective date.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

SMALLER COMPANY RISK. The Fund invests in small and mid capitalization companies. Such 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.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

PGM MINING COMPANY RISK. Securities in the Fund's portfolio may be significantly impacted by competitive pressures in the PGM mining business and the price of PGMs. Because a vast majority of the world's PGM production occurs in Russia and South Africa, the Fund's Share price may be particularly sensitive to any adverse political or economic developments affecting these countries. The Fund's Share price may experience volatility because the price of PGMs may fluctuate substantially over short periods of time. Moreover, the Index tracks companies involved in the PGM mining business and not the price of PGMs. The securities of companies involved in the PGM mining business may under- or over-perform the price of PGMs over the short term or the long term.

RUSSIA RISK. Because a significant percentage of the world's PGM mining takes place in Russia, the Fund is particularly sensitive to political and economic conditions in that country. The Fund may be affected unfavorably by political developments, social instability, changes in government policies and other political and economic developments in Russia.

SOUTH AFRICA RISK. Because a significant percentage of the world's PGM mining takes place in South Africa, the Fund is particularly sensitive to political and economic conditions in that country. South Africa has historically experienced acts of terrorism and strained international relations related to border disputes, historical animosities, racial tensions and other domestic concerns. These situations may cause uncertainty in the South African market and may adversely affect the performance of the South African economy.

PGM RISK. The Fund may be adversely affected by a decrease in the worldwide demand and price of PGMs. Various factors may lead to a decreased demand and price of PGMs. An increase in the level of hedge activity of PGM-producing companies could cause a decline in world PGM prices. A significant negative change in the attitude of speculators and investors towards PGMs could cause a decline in world PGM prices. A widening of interest rate differentials between the cost of money and the cost of PGMs could also negatively affect the price of PGMs which, in turn, could negatively affect the price of the Shares. In addition, automobile components that use PGMs account for a significant percentage of the global demand for PGMs. Because of the decline in demand and reduction in sales experienced by the global automotive industry the price of PGMs may be negatively affected. PGM companies are also subject to risks associated with the exploration, development and production of PGMs, including competition for land, difficulties in obtaining required governmental approval to mine land, inability to raise adequate capital, increases in production costs and political unrest in nations where sources of PGMs are located, particularly Russia and South Africa.

MATERIALS RISK. The Fund invests significantly in companies involved in the materials sector. General risks of the materials sector include the general state of the economy, consolidation, domestic and international politics and excess capacity. In addition, basic materials companies may also be significantly affected by volatility of commodity prices, import controls, worldwide competition, liability for environmental damage, depletion of resources and mandated expenditures for safety and pollution control devices.

NON-U.S. SECURITIES AND EMERGING MARKETS RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries. These risks may be heightened for securities of companies located in, or with significant operations in, emerging market countries.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below illustrate the annual calendar year returns of the Fund based on NAV for the past year as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. The bar chart and table provide an indication of the risks of investing in the Fund by showing how the Fund's average annual total returns based on NAV compare to those of the Index and two broad-based securities market indices. 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 Closing [Text Block]

rr_BarChartClosingTextBlock

During the year ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were -4.65% and -32.85%, respectively, for the quarters ended December 31, 2011 and 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.

1 Year

rr_AverageAnnualReturnYear01

(7.35%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(2.61%)

1 Year

rr_AverageAnnualReturnYear01

(47.60%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(47.63%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(24.07%)

1 Year

rr_AverageAnnualReturnYear01

(30.95%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 11, 2010

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.76%

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

rr_NetExpensesOverAssets

0.60%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 35% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. 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 0.60% of average daily net assets per year will be terminated following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

266

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,186

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively, "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index is developed and owned by the International Securities Exchange, LLC(R) ("ISE" or "Index Provider"), in consultation with Standard & Poor's, a Division of The McGraw-Hill Companies, Inc. ("S&P"), which calculates and maintains the Index. The Index provides a benchmark for investors interested in tracking public companies throughout the world that are active in the wind energy industry based on analysis of the products and services offered by those companies.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

SMALLER COMPANY RISK. The Fund invests in small and mid capitalization companies. Such 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.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

WIND ENERGY RISK. The Fund invests in wind energy companies. Wind energy companies 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. This can be significantly affected by fluctuations in energy prices and supply and demand of alternative energy fuels, energy conservation, the success of exploration projects and tax and other government regulations. Wind energy companies could be adversely affected by commodity price volatility, changes in exchange rates, imposition of import controls, increased competition, depletion of resources, technological developments and labor relations. In addition, the Fund may include companies affected by industry consolidation, domestic and international politics, excess capacity and consumer demand and spending trends. They may also be significantly affected by overall capital spending levels, economic cycles, delays in modernization, labor relations, government regulations and e-commerce initiatives.

INDUSTRIALS SECTOR RISK. The Fund invests in the securities of companies in the industrials sector. Many companies in this sector convert unfinished goods into finished durables used to manufacture other goods or provide services. Some industries included in this sector are electrical equipment and components, industrial products, manufactured housing and telecommunications equipment. General risks of these 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.

UTILITIES SECTOR RISK. The Fund invests in the securities of companies in the utilities sector. General problems of issuers in the utilities sector include the imposition of rate caps, increased competition due to deregulation, the difficulty in obtaining an adequate return on invested capital or in financing large construction projects, the limitations on operations and increased costs and delays attributable to environmental considerations and the capital market's ability to absorb utility debt. In addition, taxes, government regulation, international politics, price and supply fluctuations, volatile interest rates and energy conservation may cause difficulties for utilities. All of such issuers have been experiencing certain of these problems in varying degrees.

LIQUIDITY RISK. Whether or not the equity securities in the Fund are listed on a securities exchange, the principal trading market for certain of the equity securities in the Fund may be in the over-the-counter market. As a result, the existence of a liquid trading market for the equity securities may depend on whether dealers will make a market in the equity securities. There can be no assurance that a market will be made for any of the equity securities, that any market for the equity securities will be maintained or that there will be sufficient liquidity of the equity securities in any markets made. The price at which the equity securities are held in the Fund will be adversely affected if trading markets for the equity securities are limited or absent.

NON-U.S. SECURITIES RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries.

EUROPE RISK. The Fund invests a material portion of its assets in securities issued by companies operating in Europe. Investments in a single region, even though representing a number of different countries within the region, may be affected by common economic forces and other factors. The Fund is subject to greater risks of adverse events which occur in the European region and may experience greater volatility than a fund that is more broadly diversified geographically. Political or economic disruptions in European countries, even in countries in which the Fund is not invested, may adversely affect security values and thus the Fund's holdings. A significant number of countries in Europe are member states in the European Union (the "EU"), and the member states no longer control their own monetary policies by directing independent interest rates for their currencies. In these member states, the authority to direct monetary policies, including money supply and official interest rates for the Euro, is exercised by the European Central Bank. Furthermore, the European sovereign debt crisis has had, and continues to have, a significant negative impact on the economies of certain European countries and their future economic outlooks.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below illustrate the annual calendar year return of the Fund based on NAV for the past three years as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. 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 NAV compare to those of the Index and two broad-based securities market indices. 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 Closing [Text Block]

rr_BarChartClosingTextBlock

During the three-year period ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were 41.69% and -25.75%, respectively, for the quarters ended June 30, 2009 and June 30, 2010. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

1 Year

rr_AverageAnnualReturnYear01

(5.54%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 16, 2008

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

0.14%

1 Year

rr_AverageAnnualReturnYear01

(21.83%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 16, 2008

Risk/Return:

rr_RiskReturnAbstract

Annual Return 2010

rr_AnnualReturn2010

(31.42%)

1 Year

rr_AverageAnnualReturnYear01

(21.59%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 16, 2008

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(30.64%)

1 Year

rr_AverageAnnualReturnYear01

(14.00%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 16, 2008

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

^[1]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.70%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 fiscal period February 17, 2011 (inception) through September 30, 2011, the Fund's portfolio turnover rate was 29% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

269

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,135

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks and depositary receipts included in the Index.

The Fund, using an "indexing" investment approach, attempts to replicate, before fees and expenses, the performance of the Index. First Trust Advisors L.P. ("First Trust"), 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 by The NASDAQ OMX Group, Inc. (the "Index Provider"). The Index Provider and the Consumer Electronics Association have jointly developed the eligibility and selection criteria and rules for the Index. The Index is calculated and maintained by the Index Provider. The Index is designed to track the performance of companies engaged in the Smartphone segment of the telecommunications and technology sectors. The Index includes companies primarily involved in the building, design and distribution of handsets, hardware, software and mobile networks associated with the development, sale and usage of Smartphones. The Index Provider defines a Smartphone as a wireless, mobile communication device offering advanced capabilities and functionalities, including web access, through the use of an identifiable operating system.

The Index uses a modified equal dollar weighting methodology. The Index Provider evaluates the Index components semi-annually in March and September of each year for eligibility, using market data through the end of February and August, respectively. Eligible components for the Index are identified as such using the eligibility criteria set forth in this Prospectus under "Index Information." Changes to the Index are made effective after the close of trading on the third Friday in March and September. The Index is rebalanced quarterly, each March, June, September and December. As of December 31, 2011, there were 70 securities that comprised the Index.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

SMALLER COMPANY RISK. The Fund invests in small and mid capitalization companies. Such 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.

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.

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 and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

INFORMATION TECHNOLOGY COMPANIES RISK. The Fund invests in the securities of information technology companies. Information technology companies are generally subject to the risks of rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. Information technology companies may be smaller and less experienced companies, with limited product lines, markets or financial resources and fewer experienced management or marketing personnel. Information technology company stocks, particularly those involved with the Internet, have experienced extreme price and volume fluctuations that often have been unrelated to their operating performance.

SMARTPHONE INDUSTRY RISK. The Fund will be invested in securities of companies in the smartphone industry. The smartphone industry is characterized by intense competition and new market entrants, which could negatively impact profit margins and overall revenues of the companies involved in the industry. Smartphone companies are generally subject to the risks of rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards, and frequent new product introductions. Smartphone companies are affected by high and continuing costs of research and development due to quickly evolving technologies. Smartphone companies are often reliant upon the relationships with third-parties, which can be unpredictable. Additionally, the Smartphone industry is in the early stages of development and can be extremely volatile.

NON-U.S. SECURITIES AND EMERGING MARKETS RISK. The Fund invests in securities of non-U.S. issuers, including non-U.S. dollar-denominated securities traded outside of the United States and U.S. dollar-denominated securities of non-U.S. issuers traded in the United States. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries. These risks may be heightened for securities of companies located in, or with significant operations in, emerging market countries.

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 equity shares into depositary receipts and vice versa. Such restrictions may cause equity shares of the underlying issuer to trade at a discount or premium to the market price of the depositary receipts.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The Fund has not yet operated for a full calendar year and, therefore, performance information is not included in this section of the Prospectus. See "Total Return Information" for performance information regarding the Fund.

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.85%

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

rr_NetExpensesOverAssets

0.70%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 28% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. 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, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

282

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,279

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index is designed to act as a transparent and liquid benchmark for the grid and electric energy infrastructure sector. The Index includes companies that are primarily engaged and involved in electric grid, electric meters and devices, networks, energy storage and management, and enabling software used by the smart grid infrastructure sector.

Each March and September, Clean Edge, Inc. ("Clean Edge") provides The NASDAQ OMX Group, Inc. ("NASDAQ OMX") with a list of companies to be included in the Index. In order to be eligible for inclusion in the Index, the issuer of the security must be classified by Clean Edge as a smart grid, electric infrastructure and/or other grid-related activities company. Clean Edge then screens the companies identified as such using the eligibility criteria described under "Index Information." The list of remaining companies is provided to NASDAQ OMX, which then compiles the Index. NASDAQ OMX determines the respective market-capitalization weighting of each of the securities included in the Index (the "Index Securities") and balances the Index accordingly each March, June, September and December.

Clean Edge, founded in 2000, is the world's first research and publishing firm devoted to the clean-tech sector. The company, via its publications, events, and online services, helps companies, investors, and governments understand and profit from clean technologies. NASDAQ OMX is the world's largest exchange company with trading, technology and public company service capability spanning six continents.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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.

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

SMALLER COMPANY RISK. The Fund invests in small and mid capitalization companies. Such 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.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

INDUSTRIALS SECTOR RISK. The Fund invests in the securities of companies in the industrials sector. Many companies in this sector convert unfinished goods into finished durables used to manufacture other goods or provide services. Some industries included in this sector are electrical equipment and components, industrial products, manufactured housing and telecommunications equipment. General risks of these 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.

SMART GRID RISK. The Fund will be concentrated in smart grid companies. Smart grid companies can be negatively affected by high costs of research and development, high capital requirements for implementation, uncertain government regulations and input, limited ability of industrial and utility companies to quickly transform their businesses in order to implement new technologies and uncertainty of the ability of new products to penetrate established industries. Smart grid companies are often reliant upon contracts with government and commercial customers which may expire from time to time. Such companies are also affected by the general business conditions within the industrial, utility, information technology and telecommunications sectors and the overall global economy.

NON-U.S. SECURITIES RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of a Fund's holdings goes up.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below illustrate the annual calendar year returns of the Fund based on NAV for the past two years as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. The bar chart and table provide an indication of the risks of investing in the Fund by showing how the Fund's average annual total returns based on NAV compare to those of the Index and two broad-based securities market indices. 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 Closing [Text Block]

rr_BarChartClosingTextBlock

During the two-year period ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were 10.90% and -26.52%, respectively, for the quarters ended September 30, 2010 and 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.

1 Year

rr_AverageAnnualReturnYear01

1.03%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 16, 2009

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

5.65%

^[4]

1 Year

rr_AverageAnnualReturnYear01

(20.29%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 16, 2009

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

11.48%

Annual Return 2010

rr_AnnualReturn2010

(0.20%)

1 Year

rr_AverageAnnualReturnYear01

(20.90%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 16, 2009

Risk/Return:

rr_RiskReturnAbstract

Since Inception

rr_AverageAnnualReturnSinceInception

(8.02%)

1 Year

rr_AverageAnnualReturnYear01

(13.55%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 16, 2009

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

INVESTMENT OBJECTIVE

Expense [Heading]

rr_ExpenseHeading

FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

^[1]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.70%

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 fiscal period May 9, 2011 (inception) through September 30, 2011, the Fund's portfolio turnover rate was 16% of the average value of its portfolio.

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

rr_ExpenseExampleNoRedemptionYear03

269

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,135

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks included in the Index.

The Fund, using an "indexing" investment approach, attempts to replicate, before fees and expenses, the performance of the Index. First Trust Advisors L.P. ("First Trust"), 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 NASDAQ OMX Group, Inc. (the "Index Provider"). The Index Provider has contracted with Standard & Poor's to calculate and maintain the Index. The Index is designed to track the performance of the largest and most liquid companies engaged in manufacturing of automobiles.

The Index uses a modified market-capitalization weighting methodology. The Index Provider evaluates the Index components annually in June of each year for eligibility, using market data through the end of May. Eligible components for the Index are identified as such using the eligibility criteria set forth in this Prospectus under "Index Information." Changes to the Index are made effective after the close of trading on the third Friday in June. The Index is rebalanced quarterly, each March, June, September and December. As of December 31, 2011, the Index was comprised of 36 securities from nine countries, which included the United States and Japan.

The Fund intends to invest entirely 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.

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

MID-CAP STOCK RISK. The Fund invests in mid-cap company stocks, which may be subject to more abrupt or erratic market movements than those of larger, more established companies or the market averages in general.

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.

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. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issues.

AUTOMOTIVE INDUSTRY RISK. The automotive industry can be highly cyclical, and companies in the industry may suffer periodic operating losses. The industry can be significantly affected by labor relations and fluctuating component prices. While most of the major automotive manufacturers are large companies, certain others may be non-diversified in both product line and customer base and may be more vulnerable to certain events that may negatively impact the automotive industry.

CONSUMER DISCRETIONARY COMPANIES RISK. The Fund invests in consumer discretionary companies, which manufacture products and provide discretionary services directly to the consumer, and the success of these companies is tied closely to the performance of the overall domestic and international economy, interest rates, competition and consumer confidence. Success depends heavily on disposable household income and consumer spending. Changes in demographics and consumer tastes can also affect the demand for, and success of, consumer discretionary products in the marketplace.

NON-U.S. SECURITIES RISK. The Fund invests in securities of non-U.S. issuers, including non-U.S. dollar-denominated securities traded outside of the United States and U.S. dollar-denominated securities of non-U.S. issuers traded in the United States. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards and less government supervision and regulation of exchanges in foreign countries.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

JAPAN RISK. The Fund invests in the stock of companies operating in Japan. 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.

Performance Narrative [Text Block]

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The Fund has not yet operated for a full calendar year and, therefore, performance information is not included in this section of the Prospectus. See "Total Return Information" for performance information regarding the Fund.

Risk/Return:

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Objective [Heading]

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INVESTMENT OBJECTIVE

Expense [Heading]

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FEES AND EXPENSES OF THE FUND

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

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)

Distribution and Service (12b-1) Fees

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none

Total Annual Fund Operating Expenses

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1.93%

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

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0.60%

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 27% of the average value of its portfolio.

Expense Example 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 and then you retain the Shares or redeem 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 net operating expenses remain at current levels until January 31, 2013. Additionally, the example assumes that the Fund imposes a 12b-1 fee of 0.25% per annum of the Fund's average daily net assets following January 31, 2013. 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 0.60% of average daily net assets per year will be terminated following January 31, 2013. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

3 Years

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475

Expense Example, No Redemption, 10 Years

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2,344

Strategy Narrative [Text Block]

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The Fund will normally invest at least 90% of its net assets (plus the amount of any borrowings for investment purposes) in common stocks that comprise the Index or in depositary receipts that may include American Depositary Receipts ("ADRs"), Global Depositary Receipts ("GDRs"), European Depositary Receipts ("EDRs") or other depositary receipts (collectively, "Depositary Receipts") representing securities in the Index. First Trust will seek 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. First Trust 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. First Trust will regularly monitor the Fund's tracking accuracy and will seek to maintain an appropriate correlation.

The Index consists of 30 high dividend-yielding securities selected from the STOXX(R) Europe 600 Index, including secondary lines of those companies (where there are multiple lines of equity capital in a company). The STOXX(R) Europe 600 Index covers 18 European countries: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. The Index is compiled and maintained by STOXX Limited ("STOXX" or the "Index Provider"). Only dividend-paying companies in the STOXX(R) Europe 600 Index (including secondary lines of those companies) are considered for inclusion in the Index. In addition, a company must have a non-negative five-year dividend-per-share growth rate and a dividend-to-earnings ratio of 60% or less. The Index is rebalanced and reconstituted annually in March. The Fund will make changes to its portfolio holdings when changes are made by the Index Provider in the composition of 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.

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

MID-CAP STOCK RISK. The Fund invests in mid-cap company stocks, which may be subject to more abrupt or erratic market movements than those of larger, more established companies or the market averages in general.

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.

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, and the securities may be issued by companies concentrated in a particular industry. Therefore, the Fund will generally not sell a stock because the stock's issuer is in financial trouble, unless that stock is removed or is anticipated to be removed from the Index.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly concentrated in certain issuers.

FINANCIALS SECTOR RISK. The Fund invests in the securities of companies in the financials sector which may include banks, thrifts, brokerage firms, broker/dealers, investment banks, finance companies and companies involved in the insurance industry. Banks, thrifts and their holding companies are especially subject to the adverse effects of economic recession; government regulation; decreases in the availability of capital; volatile interest rates; portfolio concentrations in geographic markets and in commercial and residential real estate loans; and competition from new entrants in their fields of business. In addition, the Fund may invest in companies that may be significantly affected by the downturn in the U.S. and world economies that began with the significant decline in the subprime mortgage lending market in the United States.

INDUSTRIALS SECTOR RISK. The Fund invests in the securities of companies in the industrials sector. Many companies in this sector convert unfinished goods into finished durables used to manufacture other goods or provide services. Some industries included in this sector are electrical equipment and components, industrial products, manufactured housing and telecommunications equipment. General risks of these 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.

UNITED KINGDOM RISK. Because the Fund invests a significant portion of its assets in companies that are domiciled in the United Kingdom, the Fund is particularly sensitive to political, economic and social conditions in that country. The Fund may be affected unfavorably by political developments, social instability, changes in government policies and other political and economic developments in the United Kingdom.

EUROPE RISK. The Fund invests in securities issued by companies operating in Europe. Investments in a single region, even though representing a number of different countries within the region, may be affected by common economic forces and other factors. The Fund is subject to greater risks of adverse events which occur in the European region and may experience greater volatility than a fund that is more broadly diversified geographically. Political or economic disruptions in European countries, even in countries in which the Fund is not invested, may adversely affect security values and thus the Fund's holdings. A significant number of countries in Europe are member states in the European Union (the "EU"), and the member states no longer control their own monetary policies by directing independent interest rates for their currencies. In these member states, the authority to direct monetary policies, including money supply and official interest rates for the Euro, is exercised by the European Central Bank. Furthermore, the European sovereign debt crisis has had, and continues to have, a significant negative impact on the economies of certain European countries and their future economic outlooks.

NON-U.S. SECURITIES RISK. The Fund invests in securities of non-U.S. issuers. Such 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; excessive taxation; government seizure of assets; different legal or accounting standards; and less government supervision and regulation of exchanges in foreign countries.

CURRENCY RISK. Because the Fund's NAV is determined on the basis of U.S. dollars and the Fund invests in foreign securities, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the local currency value of the Fund's holdings goes up.

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 NAV for the past four years as well as the average annual Fund and Index returns for the one year and since inception periods ended December 31, 2011. 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 NAV compare to those of the Index and two broad-based securities market indices. 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 Closing [Text Block]

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During the four-year period ended December 31, 2011, the Fund's highest and lowest calendar quarter returns were 27.30% and -30.31%, respectively, for the quarters ended June 30, 2009 and December 31, 2008. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.