| Standard label: | Lessee, Operating Lease, Disclosure [Table Text Block] |
| Name: | us-gaap:OperatingLeasesOfLesseeDisclosureTextBlock |
| Documentation: | Tabular disclosure for lessee's operating leases. Includes, but is not limited to, description of lessee's operating lease, existence and terms of renewal or purchase options and escalation clauses, restrictions imposed by lease, such as those concerning dividends, additional debt, and further leasing, rent holidays, rent concessions, or leasehold improvement incentives and unusual provisions or conditions. |
| Object type: | cm:Level3TextBlock |
| Data type: | Text Block (HTML) (nonnum:textBlockItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OperatingLeasesOfLesseeDisclosureTextBlock |
| Examples of this text block disclosure: | OperatingLeasedAssets |
| Label | Role | Language |
| Lessee, Operating Lease, Disclosure [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 460 10 50 4 | http://fasb.org/us-gaap/role/ref/otherTransitionRef | 460 |
| FASB Accounting Standards Codification 840 10 50 2 | http://fasb.org/us-gaap/role/ref/otherTransitionRef | 840 |
| FASB Accounting Standards Codification 840 10 55 40 (Note 1,3) | http://fasb.org/us-gaap/role/ref/otherTransitionRef | 840 |
| FASB Accounting Standards Codification 840 20 50 1 | http://fasb.org/us-gaap/role/ref/otherTransitionRef | 840 |
| FASB Accounting Standards Codification 840 20 50 2 | http://fasb.org/us-gaap/role/ref/otherTransitionRef | 840 |