000000 - Document - Document and Entity Information {Elements} link:presentationLink link:calculationLink link:definitionLink 000021 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares US Quality Low Volatility Index Fund link:presentationLink link:calculationLink link:definitionLink 000021 - Schedule - Annual Fund Operating Expenses link:calculationLink link:presentationLink link:definitionLink 000041 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Developed Markets ex-US Quality Low Volatility Index Fund link:presentationLink link:calculationLink link:definitionLink 000061 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Emerging Markets Quality Low Volatility Index Fund link:presentationLink link:calculationLink link:definitionLink 000081 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Morningstar US Market Factor Tilt Index Fund link:presentationLink link:calculationLink link:definitionLink 000101 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Morningstar Developed Markets ex-US Factor Tilt Index Fund link:presentationLink link:calculationLink link:definitionLink 000121 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Morningstar Emerging Markets Factor Tilt Index Fund link:presentationLink link:calculationLink link:definitionLink 000141 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares US Quality Large Cap Index Fund link:presentationLink link:calculationLink link:definitionLink 000161 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares STOXX US ESG Select Index Fund link:presentationLink link:calculationLink link:definitionLink 000181 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares STOXX Global ESG Select Index Fund link:presentationLink link:calculationLink link:definitionLink 000201 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares ESG & Climate US Large Cap Core Index Fund link:presentationLink link:calculationLink link:definitionLink 000221 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares ESG & Climate Developed Markets ex-US Core Index Fund link:presentationLink link:calculationLink link:definitionLink 000241 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Morningstar Global Upstream Natural Resources Index Fund link:presentationLink link:calculationLink link:definitionLink 000261 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares STOXX Global Broad Infrastructure Index Fund link:presentationLink link:calculationLink link:definitionLink 000281 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Global Quality Real Estate Index Fund link:presentationLink link:calculationLink link:definitionLink 000301 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Real Assets Allocation Index Fund link:presentationLink link:calculationLink link:definitionLink 000321 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Quality Dividend Index Fund link:presentationLink link:calculationLink link:definitionLink 000341 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Quality Dividend Defensive Index Fund link:presentationLink link:calculationLink link:definitionLink 000361 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares International Quality Dividend Index Fund link:presentationLink link:calculationLink link:definitionLink 000381 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares International Quality Dividend Dynamic Index Fund link:presentationLink link:calculationLink link:definitionLink 000401 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares iBoxx 3-Year Target Duration TIPS Index Fund link:presentationLink link:calculationLink link:definitionLink 000421 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares iBoxx 5-Year Target Duration TIPS Index Fund link:presentationLink link:calculationLink link:definitionLink 000441 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Disciplined Duration MBS Index Fund link:presentationLink link:calculationLink link:definitionLink 000461 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Credit-Scored US Corporate Bond Index Fund link:presentationLink link:calculationLink link:definitionLink 000481 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Credit-Scored US Long Corporate Bond Index Fund link:presentationLink link:calculationLink link:definitionLink 000501 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares High Yield Value-Scored Bond Index Fund link:presentationLink link:calculationLink link:definitionLink 000521 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares ESG & Climate Investment Grade Corporate Core Index Fund link:presentationLink link:calculationLink link:definitionLink 000541 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Ultra-Short Income Fund link:presentationLink link:calculationLink link:definitionLink 000561 - Disclosure - Risk/Return Detail Data {Elements} - FlexShares Core Select Bond Fund link:presentationLink link:calculationLink link:definitionLink