cm:Concept: us-gaap:IncomeLossFromOngoingEquityMethodInvestmentInDiscontinuedOperationAfterDisposal
| Income (Loss) from Ongoing Equity Method Investment in Discontinued Operation after Disposal |
| us-gaap:IncomeLossFromOngoingEquityMethodInvestmentInDiscontinuedOperationAfterDisposal |
| Amount of share in income (loss) of the equity method investee after the disposal of the discontinued operation. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:IncomeLossFromOngoingEquityMethodInvestmentInDiscontinuedOperationAfterDisposal |