v3.26.1
Average Annual Total Returns
12 Months Ended 42 Months Ended
Aug. 31, 2025
Dec. 31, 2024
Dec. 31, 2024
MSCI EAFE Index (reflects no deduction for fees, expenses or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent   3.82% 2.01%
FT Vest International Equity Moderate Buffer ETF - June      
Prospectus [Line Items]      
Average Annual Return, Percent   1.46% 2.25%
Performance Inception Date Jun. 18, 2021    
FT Vest International Equity Moderate Buffer ETF - June | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent   1.46% 2.25%
FT Vest International Equity Moderate Buffer ETF - June | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent   0.86% 1.72%