cm:Concept: us-gaap:InterimPeriodCostsNotAllocableAmountFirstItem
| Interim Period, Costs Not Allocable Amount, First Item |
| us-gaap:InterimPeriodCostsNotAllocableAmountFirstItem |
| The amount of the cost or expense incurred during an interim period that cannot be readily identified with the activities or benefits of other interim periods and are charged to the interim period in which incurred. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:InterimPeriodCostsNotAllocableAmountFirstItem |