cm:Concept: us-gaap:DescriptionOfNatureOfChangesFromPriorPeriodsInMeasurementMethodsUsedToDetermineReportedSegmentProfitOrLossAndEffectOfThoseChangesOnMeasureOfSegmentProfitOrLoss
| Segment Reporting, Change in Measurement Methods |
| us-gaap:DescriptionOfNatureOfChangesFromPriorPeriodsInMeasurementMethodsUsedToDetermineReportedSegmentProfitOrLossAndEffectOfThoseChangesOnMeasureOfSegmentProfitOrLoss |
| A description of the nature of any changes from prior periods in the measurement methods used to determine reportable segment profit or loss and the effect, if any, of those changes on the measure of segment profit or loss. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DescriptionOfNatureOfChangesFromPriorPeriodsInMeasurementMethodsUsedToDetermineReportedSegmentProfitOrLossAndEffectOfThoseChangesOnMeasureOfSegmentProfitOrLoss |