cm:Concept: us-gaap:BusinessCombinationAssetsAndLiabilitiesArisingFromContingenciesDescription
| Business Combination, Assets and Liabilities Arising from Contingencies, Description |
| us-gaap:BusinessCombinationAssetsAndLiabilitiesArisingFromContingenciesDescription |
| This element represents a description of the nature of contingencies, both unrecognized and recognized, which have given rise to assets acquired and liabilities assumed at the acquisition date. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:BusinessCombinationAssetsAndLiabilitiesArisingFromContingenciesDescription |