cm:Concept: us-gaap:IncomeLossIncludingPortionAttributableToNoncontrollingInterest
| Income (Loss), Including Portion Attributable to Noncontrolling Interest, before Tax |
| us-gaap:IncomeLossIncludingPortionAttributableToNoncontrollingInterest |
| Amount, before tax, of income (loss) including portion attributable to noncontrolling interest. Includes, but is not limited to, income (loss) from continuing operations, discontinued operations and equity method investments. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:IncomeLossIncludingPortionAttributableToNoncontrollingInterest |