cm:Concept: us-gaap:MultiemployerPlansContributionRateIncreaseDecreaseDescription
| Multiemployer Plans, Contribution Rate Increase (Decrease), Description |
| us-gaap:MultiemployerPlansContributionRateIncreaseDecreaseDescription |
| Description of the nature and effect of an increase (decrease) in the contractual contribution rate on the 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:MultiemployerPlansContributionRateIncreaseDecreaseDescription |