| Standard label: | Gain on Sale of Investments |
| Name: | us-gaap:GainOnSaleOfInvestments |
| Documentation: | The difference between the carrying value and the sale price of an investment. A gain would be recognized when the sale price of the investment is greater than the carrying value of the investment. This element refers to the Gain included in earnings and not to the cash proceeds of the sale. |
| 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:GainOnSaleOfInvestments |
| Label | Role | Language |
| Gain on Sale of Investments | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03(b)(7)(c)) | http://www.xbrl.org/2009/role/commonPracticeRef | 220 |
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03(b)(9)(a)) | http://www.xbrl.org/2009/role/commonPracticeRef | 220 |
| FASB Accounting Standards Codification 230 10 45 28 (b) | http://www.xbrl.org/2009/role/commonPracticeRef | 230 |
| FASB Accounting Standards Codification 942 220 S99 1 (SX 210.9-04(13)) | http://www.xbrl.org/2009/role/commonPracticeRef | 942 |
| FASB Accounting Standards Codification 944 220 S99 1 (SX 210.7-04(3)(a)) | http://www.xbrl.org/2009/role/commonPracticeRef | 944 |