| Standard label: | Fair Value, Concentration of Risk, Market Risk Management, Value at Risk During Year [Member] |
| Name: | us-gaap:FairValueConcentrationOfRiskMarketRiskManagementValueAtRiskDuringYearMember |
| Documentation: | This item represents the average value at risk during the year from derivatives and from other positions held by the Company as of the date of the balance sheet. |
| Object type: | cm:Member |
| Data type: | [Member] (nonnum:domainItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:FairValueConcentrationOfRiskMarketRiskManagementValueAtRiskDuringYearMember |
| Label | Role | Language |
| Fair Value, Concentration of Risk, Market Risk Management, Value at Risk During Year [Member] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 825 10 50 23 (e) | http://fasb.org/us-gaap/role/ref/legacyRef | 825 |