cm:Concept: us-gaap:VariableInterestEntityReportingEntityInvolvementMaximumLossExposureNonquantifiableFlag
| Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Nonquantifiable [Fixed List] |
| us-gaap:VariableInterestEntityReportingEntityInvolvementMaximumLossExposureNonquantifiableFlag |
| An affirmative statement, as represented by "yes", that the reporting entity's maximum exposure to loss as a result of its involvement with Variable Interest Entity (VIE) cannot be quantified. |
| cm:Concept |
| Yes/No (us-types:yesNoItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:VariableInterestEntityReportingEntityInvolvementMaximumLossExposureNonquantifiableFlag |