cm:Member: us-gaap:UnclassifiedIndefinitelivedIntangibleAssetsMember
| Unclassified Indefinite-lived Intangible Assets [Member] |
| us-gaap:UnclassifiedIndefinitelivedIntangibleAssetsMember |
| Costs of contractual or legal rights meeting the criteria for capitalization as intangible assets apart from goodwill, which have indefinite life and that are not otherwise specified in the taxonomy. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:UnclassifiedIndefinitelivedIntangibleAssetsMember |