| Standard label: | Gains (Losses) on Recourse Debt |
| Name: | us-gaap:GainsLossesOnRecourseDebt |
| Documentation: | Amount represents the difference between the cash acquisition price of the debt and the net carrying amount of the debt at the time of its extinguishment. |
| 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:GainsLossesOnRecourseDebt |
| Label | Role | Language |
| Gains (Losses) on Recourse Debt | http://www.xbrl.org/2003/role/label | en-US |
| Gains (Losses) on Recourse Debt, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 470 50 40 2 | http://fasb.org/us-gaap/role/ref/legacyRef | 470 |
| FASB Accounting Standards Codification 470 50 40 4 | http://fasb.org/us-gaap/role/ref/legacyRef | 470 |
| Part Of Roll Up: |
| us-gaap:InterestAndDebtExpense |