cm:Concept: us-gaap:BusinessAcquisitionProFormaInformationDescription
| Business Acquisition, Pro Forma Information, Description |
| us-gaap:BusinessAcquisitionProFormaInformationDescription |
| Description of the pro forma information, nature of adjustments made to historical information to arrive at pro forma amounts, amounts excluded from pro forma information, any material-nonrecurring items included in the pro forma information and limitations of pro forma disclosures. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:BusinessAcquisitionProFormaInformationDescription |