cm:Level3TextBlock: us-gaap:ScheduleOfCostMethodInvestmentsTableTextBlock
| Schedule of Cost Method Investments [Table Text Block] |
| us-gaap:ScheduleOfCostMethodInvestmentsTableTextBlock |
| A tabular disclosure of (a) the aggregate carrying amount of all cost-method investments; (b) the aggregate carrying amount of cost-method investments that the investor did not evaluate for impairment for cost-method investments. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfCostMethodInvestmentsTableTextBlock |
| CostMethodInvestments |