S000046193 [Member] Expense Example - FlexShares Disciplined Duration MBS Index Fund - FlexShares Disciplined Duration MBS Index Fund	Oct. 31, 2025 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 20
Expense Example, with Redemption, 3 Years	67
Expense Example, with Redemption, 5 Years	117
Expense Example, with Redemption, 10 Years	$ 267

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