cm:Axis: us-gaap:AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis
       
          
          | Industry of Counterparty, Type [Axis] | 
       
       
          
          | us-gaap:AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis | 
       
       
          
          | Information by industry of counterparty. A counterparty is the other party that participates in a financial transaction. | 
       
       
          
          | cm:Axis | 
       
       
          
          | Text/String (xbrli:stringItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | true | 
       
       
          
          | us-gaap:AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis |