cm:Concept: us-gaap:IncomeLossFromOngoingEquityMethodInvestmentInDiscontinuedOperationAfterDisposal
       
          
          | Income (Loss) from Ongoing Equity Method Investment in Discontinued Operation after Disposal | 
       
       
          
          | us-gaap:IncomeLossFromOngoingEquityMethodInvestmentInDiscontinuedOperationAfterDisposal | 
       
       
          
          | Amount of share in income (loss) of the equity method investee after the disposal of the discontinued operation. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Credit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:IncomeLossFromOngoingEquityMethodInvestmentInDiscontinuedOperationAfterDisposal |