| Standard label: | Unrealized Gain (Loss) on Derivatives |
| Name: | us-gaap:UnrealizedGainLossOnDerivatives |
| Documentation: | The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. |
| 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:UnrealizedGainLossOnDerivatives |
| Label | Role | Language |
| Unrealized Gain (Loss) on Derivatives | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 230 10 45 28 (b) | http://fasb.org/us-gaap/role/ref/legacyRef | 230 |
| Part Of Roll Up: |
| us-gaap:UnrealizedGainLossOnDerivativesAndCommodityContracts |