cm:Concept: us-gaap:MultiemployerPlansCertifiedZoneStatusDate
| Multiemployer Plans, Certified Zone Status, Date |
| us-gaap:MultiemployerPlansCertifiedZoneStatusDate |
| Date of the multiemployer plan's year end to which the certified zone status relates, 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:MultiemployerPlansCertifiedZoneStatusDate |