v3.26.1
Average Annual Total Returns
12 Months Ended 45 Months Ended
Aug. 31, 2025
Dec. 31, 2024
Dec. 31, 2024
Nasdaq-100 Index® (reflects no deduction for fees, expenses or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent   25.88% 14.75%
S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent   25.02% 13.06%
FT Vest Nasdaq-100 Buffer ETF - March      
Prospectus [Line Items]      
Average Annual Return, Percent   16.54% 11.06%
Performance Inception Date Mar. 19, 2021    
FT Vest Nasdaq-100 Buffer ETF - March | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent   16.54% 11.06%
FT Vest Nasdaq-100 Buffer ETF - March | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent   9.79% 8.70%