| Standard label: | Valuation Allowance for Impairment of Recognized Servicing Assets, Sales | 
| Name: | us-gaap:ValuationAllowanceForImpairmentOfRecognizedServicingAssetsSales | 
| Documentation: | Reduction in valuation allowance of servicing assets based on sale of the related asset. | 
| Object type: | cm:Concept | 
| Data type: | Monetary (xbrli:monetaryItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | Debit | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ValuationAllowanceForImpairmentOfRecognizedServicingAssetsSales | 
| Label | Role | Language | 
| Valuation Allowance for Impairment of Recognized Servicing Assets, Sales | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 860 50 50 4 (e) | http://fasb.org/us-gaap/role/ref/legacyRef | 860 | 
| Part Of Roll Up: | 
| us-gaap:ValuationAllowanceForImpairmentOfRecognizedServicingAssetsSalesAndDisposals |