cm:Concept: us-gaap:MultiemployerPlansUnderfundedStatusDescription
| Multiemployer Plans, Underfunded Status, Description |
| us-gaap:MultiemployerPlansUnderfundedStatusDescription |
| Description of the extent to which the employer could be responsible for obligations of the multiemployer plan, including benefits earned by employees during employment with another employer. 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:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:MultiemployerPlansUnderfundedStatusDescription |