cm:Level3TextBlock: us-gaap:ScheduleOfReceivablesWithImputedInterestTextBlock
| Schedule of Receivables with Imputed Interest [Table Text Block] |
| us-gaap:ScheduleOfReceivablesWithImputedInterestTextBlock |
| Tabular disclosure of receivables or notes with discounts or premiums resulting from the determination of present value in cash or noncash transactions, including description of the receivable, the effective interest rate, the face amount, amortization period and method. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfReceivablesWithImputedInterestTextBlock |
| ReceivablesWithImputedInterest |