cm:Concept: us-gaap:CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAccretion
| Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Accretion |
| us-gaap:CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAccretion |
| Current period recognition due to accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesAccretableYieldAccretion |