| Standard label: | Debt Securities, Held-to-maturity, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date |
| Name: | us-gaap:DebtSecuritiesHeldToMaturityPurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate |
| Documentation: | Amount of allowance for credit loss at acquisition date of investment in debt security measured at amortized cost (held-to-maturity), purchased with credit deterioration. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:DebtSecuritiesHeldToMaturityPurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate |
| Label | Role | Language |
| Debt Securities, Held-to-maturity, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 326 20 50 19 (b) | http://www.xbrl.org/2003/role/disclosureRef | 326 |