cm:Concept: us-gaap:ReconciliationOfOperatingProfitLossFromSegmentsToConsolidated
| Reconciliation of Operating Profit (Loss) from Segments to Consolidated |
| us-gaap:ReconciliationOfOperatingProfitLossFromSegmentsToConsolidated |
| Description of reconciling items for the reconciliation of the profit (loss) from reportable segments to the consolidated income (loss) before income tax expense (benefit) and discontinued operations. Includes, but is not limited to, reconciliation after income tax if income tax is allocated to the reportable segment. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ReconciliationOfOperatingProfitLossFromSegmentsToConsolidated |