| Standard label: | Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement |
| Name: | us-gaap:DefinedBenefitPlanPurchasesSalesAndSettlements |
| Documentation: | Amount, measured using unobservable input, of increase (decrease) in plan asset of defined benefit plan from purchase, sale and settlement of trade associated with underlying investment. |
| 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:DefinedBenefitPlanPurchasesSalesAndSettlements |
| Label | Role | Language |
| Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement | http://www.xbrl.org/2003/role/label | en-US |
| Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 715 20 50 1 (d)(iv)(02)(B) | http://www.xbrl.org/2003/role/disclosureRef | 715 |
| FASB Accounting Standards Codification 715 20 55 17 | http://www.xbrl.org/2003/role/exampleRef | 715 |
| Part Of Roll Up: |
| us-gaap:DefinedBenefitPlanChangeInFairValueOfPlanAssetsLevel3ReconciliationPeriodIncreaseDecrease |