cm:Concept: us-gaap:WeightedAverageGeneralPartnershipUnitsOutstanding
       
          
          | Weighted Average General Partnership Units Outstanding | 
       
       
          
          | us-gaap:WeightedAverageGeneralPartnershipUnitsOutstanding | 
       
       
          
          | Weighted average number of general partnership units outstanding determined by relating the portion of time within a reporting period that general partnership units have been outstanding to the total time in that period. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Shares (xbrli:sharesItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | false | 
       
       
          
          | us-gaap:WeightedAverageGeneralPartnershipUnitsOutstanding |