First Trust Merger Arbitrage ETF Average Annual Total Returns |
12 Months Ended | 59 Months Ended | 60 Months Ended | 100 Months Ended | |
|---|---|---|---|---|---|
Jul. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2024 |
Dec. 31, 2024 |
Dec. 31, 2024 |
|
| S&P Merger Arbitrage Total Return Index (reflects no deduction for fees, expenses or taxes)[Member] | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 5.90% | 3.34% | |||
| S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member] | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 25.02% | 14.32% | 14.53% | 14.63% | |
| First Trust Merger Arbitrage ETF | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 0.42% | 0.94% | |||
| Performance Inception Date | Feb. 04, 2020 | ||||
| First Trust Merger Arbitrage ETF | After Taxes on Distributions | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | (0.44%) | 0.50% | |||
| First Trust Merger Arbitrage ETF | After Taxes on Distributions and Sales | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 0.24% | 0.53% |