cm:Member: us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember
| Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] |
| us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember |
| Disclosures of similar consolidated Variable Interest Entities (VIE),in aggregate, including how similar entities are aggregated, if separate reporting would not provide more useful information. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember |