| Standard label: | Federal Reserve Bank Advances [Member] |
| Name: | us-gaap:FederalReserveBankAdvancesMember |
| Documentation: | Borrowings from the Federal Reserve Bank, which are primarily used to cover shortages in the required reserve balance and also in times of liquidity shortages. |
| Object type: | cm:Member |
| Data type: | [Member] (nonnum:domainItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:FederalReserveBankAdvancesMember |
| Label | Role | Language |
| Federal Reserve Bank Advances [Member] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 942 210 S99 1 (SX 210.9-03.13(3)(a)) | http://fasb.org/us-gaap/role/ref/legacyRef | 942 |