cm:Concept: us-gaap:ProgressPaymentsNettedAgainstInventoryForLongTermContractsOrPrograms
       
          
          | Progress Payments Netted Against Inventory for Long-term Contracts or Programs | 
       
       
          
          | us-gaap:ProgressPaymentsNettedAgainstInventoryForLongTermContractsOrPrograms | 
       
       
          
          | Amount of advances received from customers under long-term contracts which have been offset against inventories accounts at the balance sheet date. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | As Of (instant) | 
       
       
          
          | Credit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:ProgressPaymentsNettedAgainstInventoryForLongTermContractsOrPrograms |