| Standard label: | Auction Market Preferred Securities, Stock Series, Title [Domain] | 
| Name: | us-gaap:AuctionMarketPreferredSecuritiesStockSeriesTitleDomain | 
| Documentation: | Title of series or issue of auction market preferred securities based on rights (names are typically labeled by day of the week, duration between intervals, or combination of both). | 
| Object type: | cm:Member | 
| Data type: | [Member] (nonnum:domainItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | (no balance type) | 
| Abstract: | true | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AuctionMarketPreferredSecuritiesStockSeriesTitleDomain | 
| Label | Role | Language | 
| Auction Market Preferred Securities, Stock Series, Title [Domain] | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| 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 | 
| FASB Accounting Standards Codification 505 10 50 4 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 | 
| FASB Accounting Standards Codification 505 10 50 5 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 | 
| FASB Accounting Standards Codification 505 10 50 11 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 |