cm:Concept: us-gaap:IncreaseDecreaseInDeferredCharges
       
          
          | Increase (Decrease) in Deferred Charges | 
       
       
          
          | us-gaap:IncreaseDecreaseInDeferredCharges | 
       
       
          
          | The increase (decrease) during the reporting period in the value of expenditures made during the current reporting period for benefits that will be received over a period of years. Deferred charges differ from prepaid expenses in that they usually extend over a long period of time and may or may not be regularly recurring costs of operation. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Credit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:IncreaseDecreaseInDeferredCharges |