cm:Concept: us-gaap:NoncontrollingInterestDecreaseFromDeconsolidation
| Noncontrolling Interest, Decrease from Deconsolidation |
| us-gaap:NoncontrollingInterestDecreaseFromDeconsolidation |
| The amount of the reduction or elimination during the period of a noncontrolling interest resulting from the parent's loss of control and deconsolidation of the entity in which one or more outside parties had a noncontrolling interest. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:NoncontrollingInterestDecreaseFromDeconsolidation |