cm:Member: us-gaap:QualitativeAndQuantitativeInformationTransferorsContinuingInvolvementInTransferredFinancialAssetsTransferOrTransfereeDomain
| Qualitative and Quantitative Information, Transferor's Continuing Involvement in Transferred Financial Assets, Transfer or Transferee [Domain] |
| us-gaap:QualitativeAndQuantitativeInformationTransferorsContinuingInvolvementInTransferredFinancialAssetsTransferOrTransfereeDomain |
| This item contains a description of the individual transfer (for example, a description of the transaction) or transferee (for example, name of a variable interest entity), to which the entity (transferor) continues to have involvement with the financial assets transferred. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:QualitativeAndQuantitativeInformationTransferorsContinuingInvolvementInTransferredFinancialAssetsTransferOrTransfereeDomain |