cm:Concept: us-gaap:OtherDeferredCompensationArrangementsLiabilityClassifiedNoncurrent
| Other Deferred Compensation Arrangements, Liability, Classified, Noncurrent |
| us-gaap:OtherDeferredCompensationArrangementsLiabilityClassifiedNoncurrent |
| Amount of the liabilities, classified as other, for deferred compensation arrangements payable after one year or the operating cycle, if longer. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:OtherDeferredCompensationArrangementsLiabilityClassifiedNoncurrent |