| Standard label: | Preferred Stock, Dividend Payment Rate, Variable | 
| Name: | us-gaap:PreferredStockDividendPaymentRateVariable | 
| Documentation: | Description of basis of dividend, such as adjustable rate. Excludes percentage rate dividend payments or fixed dollar amounts per share. | 
| Object type: | cm:Concept | 
| Data type: | Text/String (xbrli:stringItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | (no balance type) | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:PreferredStockDividendPaymentRateVariable | 
| Label | Role | Language | 
| Preferred Stock, Dividend Payment Rate, Variable | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 210 10 S99 1 (SX 210.5-02(27)) | http://fasb.org/us-gaap/role/ref/legacyRef | 210 | 
| FASB Accounting Standards Codification 210 10 S99 1 (SX 210.5-02(28)) | http://fasb.org/us-gaap/role/ref/legacyRef | 210 | 
| FASB Accounting Standards Codification 505 10 50 3 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 |