cm:Concept: us-gaap:BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable
| Business Combination, Consideration Transferred, Equity Interests Issued and Issuable |
| us-gaap:BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable |
| Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable |