| Standard label: | Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax |
| Name: | us-gaap:DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax |
| Documentation: | Amount, before tax, of unrealized gain (loss) in accumulated other comprehensive income (AOCI) 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:DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainLossBeforeTax |
| Label | Role | Language |
| Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax | http://www.xbrl.org/2003/role/label | en-US |
| Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |