v3.26.1
Average Annual Total Returns
12 Months Ended 60 Months Ended 71 Months Ended
Jul. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
ICE BofA 3-Month U.S. Treasury Bill Index (reflects no deduction for fees, expenses or taxes)[Member]        
Prospectus [Line Items]        
Average Annual Return, Percent   4.18% 3.17% 2.77%
S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member]        
Prospectus [Line Items]        
Average Annual Return, Percent   17.88% 14.42% 14.92%
First Trust Equity Market Neutral ETF        
Prospectus [Line Items]        
Average Annual Return, Percent   6.91% 2.76% 1.93%
Performance Inception Date Feb. 04, 2020      
First Trust Equity Market Neutral ETF | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent   5.61% 2.06% 1.34%
First Trust Equity Market Neutral ETF | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent   4.08% 1.82% 1.23%