cm:Concept: us-gaap:WorkersCompensationLiabilityCurrent
       
          
          | Workers' Compensation Liability, Current | 
       
       
          
          | us-gaap:WorkersCompensationLiabilityCurrent | 
       
       
          
          | Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | As Of (instant) | 
       
       
          
          | Credit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:WorkersCompensationLiabilityCurrent |