cm:Concept: us-gaap:InterestExpenseLesseeAssetsUnderCapitalLease
       
          
          | Interest Expense, Lessee, Assets under Capital Lease | 
       
       
          
          | us-gaap:InterestExpenseLesseeAssetsUnderCapitalLease | 
       
       
          
          | The amount, during the lease term, of each minimum [capital] lease payment allocated to interest expense so as to produce a constant periodic rate of interest on the remaining balance of the capital lease obligation. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Debit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:InterestExpenseLesseeAssetsUnderCapitalLease |