cm:Concept: us-gaap:BusinessCombinationProvisionalInformationInitialAccountingIncompleteItems
| Business Combination, Provisional Information, Initial Accounting Incomplete, Items |
| us-gaap:BusinessCombinationProvisionalInformationInitialAccountingIncompleteItems |
| This element represents a statement of which of the assets, liabilities, equity interests, recognized in the financial statements or items of consideration transferred for which the initial accounting is incomplete in connection with a business combination occurring during the period. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:BusinessCombinationProvisionalInformationInitialAccountingIncompleteItems |