cm:Level3TextBlock: us-gaap:ScheduleOfMultiemployerPlansTableTextBlock
| Schedule of Multiemployer Plans [Table Text Block] |
| us-gaap:ScheduleOfMultiemployerPlansTableTextBlock |
| Tabular disclosure of the quantitative and qualitative information related to multiemployer plans in which the employer participates. 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. |
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| Text Block (HTML) (nonnum:textBlockItemType) |
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| us-gaap:ScheduleOfMultiemployerPlansTableTextBlock |