| Standard label: | AOCI, Debt Securities, Available-for-sale, Adjustment, after Tax |
| Name: | us-gaap:AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax |
| Documentation: | Amount, after tax, of accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). |
| 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:AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax |
| Label | Role | Language |
| AOCI, Debt Securities, Available-for-sale, Adjustment, after Tax | http://www.xbrl.org/2003/role/label | en-US |
| AOCI, Debt Securities, Available-for-sale, Adjustment, after Tax, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 220 10 45 14 | http://www.xbrl.org/2009/role/commonPracticeRef | 220 |
| Part Of Roll Up: |
| us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax |