| Standard label: | Affordable Housing Project Investment, Write-down, Amount |
| Name: | us-gaap:AffordableHousingProjectInvestmentWriteDownAmount |
| Documentation: | Amount of write-down from impairment of an investment in a qualified affordable housing project. |
| 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:AffordableHousingProjectInvestmentWriteDownAmount |
| Label | Role | Language |
| Affordable Housing Project Investment, Write-down, Amount | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 323 740 50 2 (f) | http://fasb.org/us-gaap/role/ref/legacyRef | 323 |
| Part Of Roll Up: |
| us-gaap:AssetImpairmentCharges |