cm:Concept: us-gaap:IndefiniteLivedContractualRights
| Indefinite-Lived Contractual Rights |
| us-gaap:IndefiniteLivedContractualRights |
| Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date of rights with an indefinite period of benefit that arose from a contractual arrangement with a third party (not including franchise rights and license agreements). |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:IndefiniteLivedContractualRights |