cm:Concept: us-gaap:NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable
| Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Nonredeemable |
| us-gaap:NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable |
| Amount after tax of income (loss) attributable to nonredeemable noncontrolling shareholder, unit holder, partner, or other equity holder of a joint venture. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable |