cm:Concept: us-gaap:DescriptionOfTypesOfProductsAndServicesFromWhichEachReportableSegmentDerivesItsRevenues
| Segment Reporting Information, Description of Products and Services |
| us-gaap:DescriptionOfTypesOfProductsAndServicesFromWhichEachReportableSegmentDerivesItsRevenues |
| Description of the types of products and services from which the reportable segment derives its revenue. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DescriptionOfTypesOfProductsAndServicesFromWhichEachReportableSegmentDerivesItsRevenues |