110001 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Investment Objectives and Goals link:presentationLink link:definitionLink link:calculationLink 110002 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Fees and Expenses link:presentationLink link:definitionLink link:calculationLink 110003 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Investment Strategy link:presentationLink link:definitionLink link:calculationLink 110004 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Investment Risks link:presentationLink link:definitionLink link:calculationLink 110005 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Performance Management link:presentationLink link:definitionLink link:calculationLink 120010 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Shareholder Fees link:presentationLink link:definitionLink link:calculationLink 120020 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Annual Fund Operating Expenses link:presentationLink link:definitionLink link:calculationLink 120030 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Expense Example link:presentationLink link:definitionLink link:calculationLink 120040 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Expense Example, No Redemption link:presentationLink link:definitionLink link:calculationLink 120045 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Risks Data link:presentationLink link:definitionLink link:calculationLink 120050 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 120060 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Average Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 120070 - Disclosure - First Trust Dorsey Wright DALI Equity ETF Market Index Performance link:presentationLink link:definitionLink link:calculationLink 110000 - Disclosure - First Trust Dorsey Wright DALI Equity ETF N-1A Cover link:presentationLink link:definitionLink link:calculationLink 210001 - Disclosure - First Trust BuyWrite Income ETF Investment Objectives and Goals link:presentationLink link:definitionLink link:calculationLink 210002 - Disclosure - First Trust BuyWrite Income ETF Fees and Expenses link:presentationLink link:definitionLink link:calculationLink 210003 - Disclosure - First Trust BuyWrite Income ETF Investment Strategy link:presentationLink link:definitionLink link:calculationLink 210004 - Disclosure - First Trust BuyWrite Income ETF Investment Risks link:presentationLink link:definitionLink link:calculationLink 210005 - Disclosure - First Trust BuyWrite Income ETF Performance Management link:presentationLink link:definitionLink link:calculationLink 220010 - Disclosure - First Trust BuyWrite Income ETF Shareholder Fees link:presentationLink link:definitionLink link:calculationLink 220020 - Disclosure - First Trust BuyWrite Income ETF Annual Fund Operating Expenses link:presentationLink link:definitionLink link:calculationLink 220030 - Disclosure - First Trust BuyWrite Income ETF Expense Example link:presentationLink link:definitionLink link:calculationLink 220040 - Disclosure - First Trust BuyWrite Income ETF Expense Example, No Redemption link:presentationLink link:definitionLink link:calculationLink 220045 - Disclosure - First Trust BuyWrite Income ETF Risks Data link:presentationLink link:definitionLink link:calculationLink 220050 - Disclosure - First Trust BuyWrite Income ETF Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 220060 - Disclosure - First Trust BuyWrite Income ETF Average Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 220070 - Disclosure - First Trust BuyWrite Income ETF Market Index Performance link:presentationLink link:definitionLink link:calculationLink 210000 - Disclosure - First Trust BuyWrite Income ETF N-1A Cover link:presentationLink link:definitionLink link:calculationLink 310001 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Investment Objectives and Goals link:presentationLink link:definitionLink link:calculationLink 310002 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Fees and Expenses link:presentationLink link:definitionLink link:calculationLink 310003 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Investment Strategy link:presentationLink link:definitionLink link:calculationLink 310004 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Investment Risks link:presentationLink link:definitionLink link:calculationLink 310005 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Performance Management link:presentationLink link:definitionLink link:calculationLink 320010 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Shareholder Fees link:presentationLink link:definitionLink link:calculationLink 320020 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Annual Fund Operating Expenses link:presentationLink link:definitionLink link:calculationLink 320030 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Expense Example link:presentationLink link:definitionLink link:calculationLink 320040 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Expense Example, No Redemption link:presentationLink link:definitionLink link:calculationLink 320045 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Risks Data link:presentationLink link:definitionLink link:calculationLink 320050 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 320060 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Average Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 320070 - Disclosure - First Trust Nasdaq BuyWrite Income ETF Market Index Performance link:presentationLink link:definitionLink link:calculationLink 310000 - Disclosure - First Trust Nasdaq BuyWrite Income ETF N-1A Cover link:presentationLink link:definitionLink link:calculationLink 410001 - Disclosure - First Trust Small Cap BuyWrite Income ETF Investment Objectives and Goals link:presentationLink link:definitionLink link:calculationLink 410002 - Disclosure - First Trust Small Cap BuyWrite Income ETF Fees and Expenses link:presentationLink link:definitionLink link:calculationLink 410003 - Disclosure - First Trust Small Cap BuyWrite Income ETF Investment Strategy link:presentationLink link:definitionLink link:calculationLink 410004 - Disclosure - First Trust Small Cap BuyWrite Income ETF Investment Risks link:presentationLink link:definitionLink link:calculationLink 410005 - Disclosure - First Trust Small Cap BuyWrite Income ETF Performance Management link:presentationLink link:definitionLink link:calculationLink 420010 - Disclosure - First Trust Small Cap BuyWrite Income ETF Shareholder Fees link:presentationLink link:definitionLink link:calculationLink 420020 - Disclosure - First Trust Small Cap BuyWrite Income ETF Annual Fund Operating Expenses link:presentationLink link:definitionLink link:calculationLink 420030 - Disclosure - First Trust Small Cap BuyWrite Income ETF Expense Example link:presentationLink link:definitionLink link:calculationLink 420040 - Disclosure - First Trust Small Cap BuyWrite Income ETF Expense Example, No Redemption link:presentationLink link:definitionLink link:calculationLink 420045 - Disclosure - First Trust Small Cap BuyWrite Income ETF Risks Data link:presentationLink link:definitionLink link:calculationLink 420050 - Disclosure - First Trust Small Cap BuyWrite Income ETF Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 420060 - Disclosure - First Trust Small Cap BuyWrite Income ETF Average Annual Total Returns link:presentationLink link:definitionLink link:calculationLink 420070 - Disclosure - First Trust Small Cap BuyWrite Income ETF Market Index Performance link:presentationLink link:definitionLink link:calculationLink 410000 - Disclosure - First Trust Small Cap BuyWrite Income ETF N-1A Cover link:presentationLink link:definitionLink link:calculationLink First Trust Dorsey Wright DALI Equity ETF S000061869 [Member] C000200399 [Member] Nasdaq Dorsey Wright DALI Equity(TM) Index (reflects no deduction for fees, expenses or taxes)[Member] S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member] Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)[Member] Authorized Participant Concentration Risk [Member] China Risk [Member] Concentrated Investment Risk [Member] Conflict Of Interest Risk [Member] Currency Risk [Member] Current Market Conditions Risk [Member] Cyber Security Risk [Member] Depositary Receipts Risk [Member] Emerging Markets Risk [Member] Equity Securities Risk [Member] ETF Risk [Member] Europe Risk [Member] Index Concentration Risk [Member] Index Provider Risk [Member] Index Rebalance Risk [Member] Large Capitalization Companies Risk [Member] Market Maker Risk [Member] Market Risk [Member] Momentum Investing Risk [Member] Non Correlation Risk [Member] Non US Securities Risk [Member] Operational Risk [Member] Passive Investment Risk [Member] Portfolio Turnover Risk [Member] Premium Discount Risk [Member] Smaller Companies Risk [Member] Trading Issues Risk [Member] First Trust BuyWrite Income ETF S000040302 [Member] C000125197 [Member] CBOE S&P 500® BuyWrite Index(SM) (reflects no deduction for fees, expenses or taxes)[Member] Call Options Risk [Member] Counterparty Risk [Member] Derivatives Risk [Member] Distribution Tax Risk [Member] Dividends Risk [Member] Index Or Model Constituent Risk [Member] Inflation Risk [Member] Information Technology Companies Risk [Member] Liquidity Risk [Member] Management Risk [Member] MLP Risk [Member] Options Risk [Member] Portfolio Correlation Risk [Member] REIT Risk [Member] Significant Exposure Risk [Member] Tax Risks Associated With Investment In Options [Member] Valuation Risk [Member] First Trust Nasdaq BuyWrite Income ETF S000040305 [Member] C000125204 [Member] Cboe Nasdaq-100 BuyWrite(TM) Index (reflects no deduction for fees, expenses or taxes)[Member] Nasdaq-100 Index® (reflects no deduction for fees, expenses or taxes)[Member] Mid Capitalization Companies Risk [Member] Small Capitalization Companies Risk [Member] Tax Risks Associated With Investment In Options On Indexes [Member] First Trust Small Cap BuyWrite Income ETF S000090516 [Member] C000257781 [Member] Risk Nondiversified [Member]