S000050613 [Member] Expense Example - FlexShares Credit-Scored US Long Corporate Bond Index Fund - FlexShares Credit-Scored US Long Corporate Bond Index Fund	Oct. 31, 2025 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 15
Expense Example, with Redemption, 3 Years	51
Expense Example, with Redemption, 5 Years	89
Expense Example, with Redemption, 10 Years	$ 204

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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