| Standard label: | Off-Balance Sheet, Credit Loss, Liability |
| Name: | us-gaap:OffBalanceSheetCreditLossLiability |
| Documentation: | Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OffBalanceSheetCreditLossLiability |
| Label | Role | Language |
| Off-Balance Sheet, Credit Loss, Liability | http://www.xbrl.org/2003/role/label | en-US |
| Off-Balance Sheet, Credit Loss, Liability, Ending Balance | http://www.xbrl.org/2003/role/periodEndLabel | en-US |
| Off-Balance Sheet, Credit Loss, Liability, Beginning Balance | http://www.xbrl.org/2003/role/periodStartLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 326 20 45 2 | http://www.xbrl.org/2003/role/disclosureRef | 326 |
| FASB Accounting Standards Codification 460 10 45 1 | http://www.xbrl.org/2003/role/disclosureRef | 460 |