cm:Level1TextBlock: us-gaap:BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCostsTextBlock
| Business Acquisition, Integration, Restructuring and Other Related Costs [Text Block] |
| us-gaap:BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCostsTextBlock |
| The entire description for costs incurred to effect a business combination that have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCostsTextBlock |
| BusinessAcquisitionIntegrationRestructuringAndOtherRelatedCosts |