S000055516 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 109 Months Ended | ||
|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| Bloomberg U.S. Aggregate Bond Index | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | [1] | 7.30% | (0.36%) | 1.92% | |
| FlexShares Core Select Bond Fund | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 7.20% | (0.66%) | 1.75% | ||
| Performance Inception Date | Nov. 18, 2016 | ||||
| FlexShares Core Select Bond Fund | After Taxes on Distributions | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 5.38% | (1.90%) | 0.52% | ||
| FlexShares Core Select Bond Fund | After Taxes on Distributions and Sales | |||||
| Prospectus [Line Items] | |||||
| Average Annual Return, Percent | 4.23% | (1.04%) | 0.80% | ||
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