| Standard label: | Option Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value |
| Name: | us-gaap:OptionIndexedToIssuersEquitySettlementAlternativesCashAtFairValue |
| Documentation: | Fair value of each cash settlement alternative for each freestanding option contract. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OptionIndexedToIssuersEquitySettlementAlternativesCashAtFairValue |
| Label | Role | Language |
| Option Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 815 40 50 5 (d) | http://fasb.org/us-gaap/role/ref/legacyRef | 815 |