cm:Concept: us-gaap:ProceedsFromSalesOfAssetsInvestingActivities
       
          
          | Proceeds from Sales of Assets, Investing Activities | 
       
       
          
          | us-gaap:ProceedsFromSalesOfAssetsInvestingActivities | 
       
       
          
          | Aggregate cash proceeds received from a combination of transactions that are classified as investing activities in which assets, which may include one or more investments, are sold to third-party buyers. This element can be used by entities to aggregate proceeds from all asset sales that are classified as investing activities. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Debit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:ProceedsFromSalesOfAssetsInvestingActivities |