cm:Concept: us-gaap:IncreaseDecreaseInEarnestMoneyDepositsOutstanding
       
          
          | Increase (Decrease) in Earnest Money Deposits Outstanding | 
       
       
          
          | us-gaap:IncreaseDecreaseInEarnestMoneyDepositsOutstanding | 
       
       
          
          | The increase (decrease) during the reporting period in the amount of deposits given by the reporting entity to a seller which shows that the prospective buyer is serious about purchasing a property. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Credit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:IncreaseDecreaseInEarnestMoneyDepositsOutstanding |