| Standard label: | Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Other, Percentage of Nonperforming Assets |
| Name: | us-gaap:HeldtomaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureOtherPercentageOfNonperformingAssets |
| Documentation: | This item represents the percentage of nonperforming assets that the underlying assets in the security represent and which were considered as one of the potential factors in reaching a conclusion that the held-to-maturity investments are not other-than-temporarily impaired. |
| Object type: | cm:Concept |
| Data type: | Percent (num:percentItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:HeldtomaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureOtherPercentageOfNonperformingAssets |
| Label | Role | Language |
| Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Other, Percentage of Nonperforming Assets | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 50 6 | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |