cm:Concept: us-gaap:ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans
| Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans |
| us-gaap:ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans |
| The cash inflow from proceeds From Sales of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans |