First Trust SMID Capital Strength ETF Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 102 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|
Mar. 31, 2026 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| The SMID Capital Strength Index (reflects no deduction for fees, expenses or taxes)[Member] | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | [1],[2] | 2.21% | ||||||
| Russell 2500(TM) Index (reflects no deduction for fees, expenses or taxes)[Member] | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 11.91% | 7.26% | 9.52% | |||||
| Russell 3000® Index (reflects no deduction for fees, expenses or taxes)[Member] | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 17.15% | 13.15% | 14.12% | |||||
| First Trust SMID Capital Strength ETF | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 1.57% | 9.46% | 8.71% | |||||
| Performance Inception Date | Jun. 20, 2017 | |||||||
| First Trust SMID Capital Strength ETF | After Taxes on Distributions | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 1.26% | 8.88% | 8.08% | |||||
| First Trust SMID Capital Strength ETF | After Taxes on Distributions and Sales | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 0.93% | 7.20% | 6.71% | |||||
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