cm:Concept: us-gaap:AmountOfRegulatoryAssistanceReceived1
| Amount of Regulatory Assistance Received |
| us-gaap:AmountOfRegulatoryAssistanceReceived1 |
| Amount of regulatory assistance received from a federal regulatory agency in conjunction with either an acquisition of a troubled financial institution, transfer of nonperforming assets to a newly-formed entity, or other reorganization. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:AmountOfRegulatoryAssistanceReceived1 |