| Standard label: | Proceeds from Sale of Loans and Leases Held-for-investment |
| Name: | us-gaap:ProceedsFromSaleOfLoansAndLeasesHeldForInvestment |
| Documentation: | The net cash inflow from (a) sales of loans held-for-investment, (b) sales of leases held-for-investment, and (c) both. Includes proceeds from securitizations of loans. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ProceedsFromSaleOfLoansAndLeasesHeldForInvestment |
| Label | Role | Language |
| Proceeds from Sale of Loans and Leases Held-for-investment | http://www.xbrl.org/2003/role/label | en-US |
| Proceeds from Sale of Loans and Leases Held-for-investment, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 230 10 45 12 (a) | http://fasb.org/us-gaap/role/ref/legacyRef | 230 |
| Part Of Roll Up: |
| us-gaap:PaymentsForProceedsFromLoansAndLeases |