cm:Level3TextBlock: us-gaap:AccountsReceivableNoncurrentCreditQualityIndicatorTableTextBlock
| Accounts Receivable, Noncurrent, Credit Quality Indicator [Table Text Block] |
| us-gaap:AccountsReceivableNoncurrentCreditQualityIndicatorTableTextBlock |
| Tabular disclosure of credit quality indicator for accounts receivable, classified as noncurrent. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:AccountsReceivableNoncurrentCreditQualityIndicatorTableTextBlock |