S000033312 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended | ||
|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| Russell 3000 Index | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | [1] | 17.15% | 13.15% | 14.28% | |
| Morningstar® US Market Factor Tilt Index℠ | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | [1] | 16.75% | 13.19% | 13.42% | |
| FlexShares Morningstar US Market Factor Tilt Index Fund | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 16.41% | 12.95% | 13.25% | ||
| FlexShares Morningstar US Market Factor Tilt Index Fund | After Taxes on Distributions | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 16.00% | 12.53% | 12.78% | ||
| FlexShares Morningstar US Market Factor Tilt Index Fund | After Taxes on Distributions and Sales | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 9.86% | 10.24% | 10.94% | ||
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