cm:Concept: us-gaap:MultiemployerPlansCollectiveBargainingArrangementExpirationDate
| Multiemployer Plans, Collective-Bargaining Arrangement, Expiration Date |
| us-gaap:MultiemployerPlansCollectiveBargainingArrangementExpirationDate |
| Expiration date of the collective bargaining arrangement requiring contributions to the multiemployer plan, in CCYY-MM-DD format. 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 |
| Date (xbrli:dateItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:MultiemployerPlansCollectiveBargainingArrangementExpirationDate |