cm:Concept: us-gaap:DeferredSubscriberAcquisitionCostsCurrent
       
          
          | Deferred Subscriber Acquisition Costs, Current | 
       
       
          
          | us-gaap:DeferredSubscriberAcquisitionCostsCurrent | 
       
       
          
          | Costs deferred when a service provider provides incentives to third-party manufacturers or resellers to reduce the selling prices of specialized equipment in order to stimulate end-customer demand for the service provider's offerings. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | As Of (instant) | 
       
       
          
          | Debit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:DeferredSubscriberAcquisitionCostsCurrent |