| Standard label: | Adjustments to Additional Paid in Capital, Fair Value |
| Name: | us-gaap:AdjustmentsToAdditionalPaidInCapitalMarkToMarket |
| Documentation: | Amount of increase (decrease) to additional paid in capital (APIC) resulting from changes in fair value of common and preferred stock issued to employee benefit trust but unearned. |
| 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:AdjustmentsToAdditionalPaidInCapitalMarkToMarket |
| Label | Role | Language |
| Adjustments to Additional Paid in Capital, Fair Value | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 505 10 S99 1 (SX 210.3-04) | http://fasb.org/us-gaap/role/ref/legacyRef | 505 |
| FASB Accounting Standards Codification 505 10 50 2 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 |
| Part Of Roll Up: |
| us-gaap:StockholdersEquityPeriodIncreaseDecrease |