cm:Table: us-gaap:ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleTable
| Impaired Assets to be Disposed of by Method Other than Sale [Table] |
| us-gaap:ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleTable |
| When an entity determines it will dispose of a long-lived asset by a method other than sale (for example, by abandonment, distribution in a spin-off), impairment of such assets is separately disclosed from those assets held and used. |
| cm:Table |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleTable |