| Standard label: | Auction Market Preferred Securities, Shares, Issued |
| Name: | us-gaap:AuctionMarketPreferredSecuritiesSharesIssued |
| Documentation: | Number of auction market preferred securities shares issued. |
| Object type: | cm:Concept |
| Data type: | Shares (xbrli:sharesItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AuctionMarketPreferredSecuritiesSharesIssued |
| Label | Role | Language |
| Auction Market Preferred Securities, Shares, Issued | 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 |
| Part Of Roll Up: |
| us-gaap:AuctionMarketPreferredSecuritiesStockSharesOutstandingPeriodIncreaseDecrease |