cm:Level3TextBlock: us-gaap:ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock
| Schedule of Finite-Lived Intangible Assets [Table Text Block] |
| us-gaap:ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock |
| Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite life, by either major class or business segment. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock |
| FiniteLivedIntangibleAssetsNetRollUp |