cm:Level3TextBlock: us-gaap:ScheduleOfIndefiniteLivedIntangibleAssetsTableTextBlock
| Schedule of Indefinite-Lived Intangible Assets [Table Text Block] |
| us-gaap:ScheduleOfIndefiniteLivedIntangibleAssetsTableTextBlock |
| Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance and exist in perpetuity, by either major class or business segment. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfIndefiniteLivedIntangibleAssetsTableTextBlock |
| IndefinitelivedIntangibleAssets |