cm:Concept: us-gaap:BusinessCombinationIndemnificationAssetsRangeOfOutcomesMaximumUnlimited
| Business Combination, Indemnification Assets, Range of Outcomes, Maximum Unlimited |
| us-gaap:BusinessCombinationIndemnificationAssetsRangeOfOutcomesMaximumUnlimited |
| For indemnification assets recognized in connection with a business combination, if the maximum (undiscounted) potential outcome is limitless, this element represents a statement of that fact. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:BusinessCombinationIndemnificationAssetsRangeOfOutcomesMaximumUnlimited |