| Standard label: | Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions |
| Name: | us-gaap:AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1 |
| Documentation: | Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. |
| Object type: | cm:Concept |
| Data type: | Integer (xbrli:integerItemType) |
| Period type: | As Of (instant) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1 |
| Label | Role | Language |
| Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | http://www.xbrl.org/2003/role/label | en-US |
| Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 50 6 (b)(3) | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |