cm:Concept: us-gaap:RestructuringAndRelatedActivitiesLiabilityNotRecognized
| Restructuring and Related Activities, Liability Not Recognized |
| us-gaap:RestructuringAndRelatedActivitiesLiabilityNotRecognized |
| Description of restructuring costs that have not been recognized as a liability because fair value cannot be reasonably estimated. The description is expected to include the reasons why fair value cannot be reasonably estimated. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:RestructuringAndRelatedActivitiesLiabilityNotRecognized |