cm:Concept: us-gaap:DiscontinuedOperationContinuationOfActivitiesWithDiscontinuedOperationAfterDisposalDescription
| Discontinued Operation, Nature of Activities Having Continuing Involvement after Disposal |
| us-gaap:DiscontinuedOperationContinuationOfActivitiesWithDiscontinuedOperationAfterDisposalDescription |
| Description of the nature of activities that give rise to the continuing involvement with a discontinued operation after disposal. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DiscontinuedOperationContinuationOfActivitiesWithDiscontinuedOperationAfterDisposalDescription |