cm:Concept: us-gaap:ProceedsFromIssuanceOfFirstMortgageBond
       
          
          | Proceeds from Issuance of First Mortgage Bond | 
       
       
          
          | us-gaap:ProceedsFromIssuanceOfFirstMortgageBond | 
       
       
          
          | The cash inflow from amounts received from a long-term debt instrument secured by a first mortgage deed of trust, containing a pledge of real property. The lender has the highest claim on the property in case of default. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Debit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:ProceedsFromIssuanceOfFirstMortgageBond |