cm:Concept: us-gaap:RevenuePracticalExpedientRemainingPerformanceObligationDescription
| Revenue, Practical Expedient, Remaining Performance Obligation, Description |
| us-gaap:RevenuePracticalExpedientRemainingPerformanceObligationDescription |
| Description of consideration that is not included in transaction price and not allocated to remaining performance obligation. Includes, but is not limited to, variable consideration that is constrained. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:RevenuePracticalExpedientRemainingPerformanceObligationDescription |