| Standard label: | Defined Benefit Plan, Equity Securities [Member] |
| Name: | us-gaap:DefinedBenefitPlanEquitySecuritiesMember |
| Documentation: | Security representing ownership in corporation or other legal entity for which ownership is represented by share of stock, in which defined benefit plan asset is invested. Includes, but is not limited to, common stock, preferred stock, convertible security, stock right and stock warrant. |
| 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:DefinedBenefitPlanEquitySecuritiesMember |
| Label | Role | Language |
| Defined Benefit Plan, Equity Securities [Member] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 715 20 50 1 (d)(ii) | http://www.xbrl.org/2003/role/exampleRef | 715 |
| FASB Accounting Standards Codification 715 20 55 17 | http://www.xbrl.org/2003/role/exampleRef | 715 |