cm:Concept: us-gaap:RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer
| Revenue from Collaborative Arrangement, Excluding Revenue from Contract with Customer |
| us-gaap:RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer |
| Amount of revenue from collaborative arrangement. Excludes revenue from contract with customer under Topic 606. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer |