cm:Level3TextBlock: us-gaap:RevenueFromExternalCustomersByGeographicAreasTableTextBlock
| Revenue from External Customers by Geographic Areas [Table Text Block] |
| us-gaap:RevenueFromExternalCustomersByGeographicAreasTableTextBlock |
| Tabular disclosure of revenue from external customers by geographic areas attributed to the entity's country of domicile and to foreign countries from which the entity derives revenue. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:RevenueFromExternalCustomersByGeographicAreasTableTextBlock |
| GeographicAreasRevenuesfromExternalCustomers |