cm:Axis: us-gaap:MultiemployerPlanPlanInformationAxis
| Multiemployer Plan, Plan Information [Axis] |
| us-gaap:MultiemployerPlanPlanInformationAxis |
| Information by whether or not the plan level information for a multiemployer plan is available in the public domain. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. |
| cm:Axis |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:MultiemployerPlanPlanInformationAxis |