| Standard label: | Debt and Equity Securities, Gain (Loss) |
| Name: | us-gaap:DebtAndEquitySecuritiesGainLoss |
| Documentation: | Amount of unrealized and realized gain (loss) on investment in debt and equity securities. |
| 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:DebtAndEquitySecuritiesGainLoss |
| Label | Role | Language |
| Debt and Equity Securities, Gain (Loss) | http://www.xbrl.org/2003/role/label | en-US |
| Debt and Equity Securities, Gain (Loss), Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03(7)(c)) | http://fasb.org/us-gaap/role/ref/legacyRef | 220 |
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03(9)(a)) | http://fasb.org/us-gaap/role/ref/legacyRef | 220 |