cm:Concept: us-gaap:EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards
| Share-based Payment Arrangement, Cash Used to Settle Award |
| us-gaap:EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards |
| Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards |