cm:Member: us-gaap:WarrantsAndRightsSubjectToMandatoryRedemptionMember
       
          
          | Warrants and Rights Subject to Mandatory Redemption [Member] | 
       
          
          | us-gaap:WarrantsAndRightsSubjectToMandatoryRedemptionMember | 
       
          
          | Warrants and rights that embody an unconditional obligation requiring the issuer to redeem the instrument by transferring its assets at a specified or determinable date (or dates) or upon an event certain to occur. | 
       
          
          | cm:Member | 
       
          
          | [Member] (nonnum:domainItemType) | 
       
          
          | For Period (duration) | 
       
          
          | (no balance type) | 
       
          
          | true | 
       
          
          | us-gaap:WarrantsAndRightsSubjectToMandatoryRedemptionMember |