cm:Concept: us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestructuringLiabilities
| Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Restructuring Liabilities |
| us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestructuringLiabilities |
| This item represents liabilities associated with restructuring or exit activities of the acquiree, existing at the acquisition date (present liabilities of the acquiree). |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestructuringLiabilities |