cm:Concept: us-gaap:DescriptionOfNatureOfDifferencesBetweenMeasurementsOfReportableSegmentsProfitsOrLossesAndEntitysProfitOrLossBeforeIncomeTaxExpenseOrIncomeAndDiscontinuedOperations
| Segment Reporting, Measurement Differences Between Segment and Consolidated Profit (Loss) |
| us-gaap:DescriptionOfNatureOfDifferencesBetweenMeasurementsOfReportableSegmentsProfitsOrLossesAndEntitysProfitOrLossBeforeIncomeTaxExpenseOrIncomeAndDiscontinuedOperations |
| Description of the nature of differences between the measurement of reportable segment profit (loss) and consolidated income before income taxes and discontinued operations. Includes, but is not limited to, accounting policies and policies for allocation of centrally incurred costs. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DescriptionOfNatureOfDifferencesBetweenMeasurementsOfReportableSegmentsProfitsOrLossesAndEntitysProfitOrLossBeforeIncomeTaxExpenseOrIncomeAndDiscontinuedOperations |