cm:Concept: us-gaap:BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1
| Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability |
| us-gaap:BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1 |
| Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1 |