S000054498 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 114 Months Ended | ||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| STOXX® USA ESG Select KPIs Index℠ | |||||||
| Prospectus [Line Items] | |||||||
| Average Annual Return, Percent | [1],[2] | 15.80% | 12.81% | 14.16% | |||
| Russell 1000® Index | |||||||
| Prospectus [Line Items] | |||||||
| Average Annual Return, Percent | [2] | 17.37% | 13.59% | 14.70% | |||
| FlexShares STOXX US ESG Select Index Fund | |||||||
| Prospectus [Line Items] | |||||||
| Average Annual Return, Percent | 15.88% | 12.92% | 14.54% | ||||
| Performance Inception Date | Jul. 13, 2016 | ||||||
| FlexShares STOXX US ESG Select Index Fund | After Taxes on Distributions | |||||||
| Prospectus [Line Items] | |||||||
| Average Annual Return, Percent | 15.60% | 12.60% | 14.15% | ||||
| FlexShares STOXX US ESG Select Index Fund | After Taxes on Distributions and Sales | |||||||
| Prospectus [Line Items] | |||||||
| Average Annual Return, Percent | 9.58% | 10.28% | 12.11% | ||||
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