cm:Concept: us-gaap:IncreaseDecreaseInSelfInsuranceReserve
       
          
          | Increase (Decrease) in Self Insurance Reserve | 
       
       
          
          | us-gaap:IncreaseDecreaseInSelfInsuranceReserve | 
       
       
          
          | The increase (decrease) during the period in the carrying amount of accrued known and estimated losses incurred for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's' compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Debit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:IncreaseDecreaseInSelfInsuranceReserve |