cm:Level3TextBlock: us-gaap:FairValueLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock
| Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis [Table Text Block] |
| us-gaap:FairValueLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock |
| Tabular disclosure of liabilities measured at fair value measured on a recurring or nonrecurring basis. Includes, but is not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:FairValueLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock |