cm:Member: us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember
       
          
          | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] | 
       
       
          
          | us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember | 
       
       
          
          | Accumulated other comprehensive income (loss) from gain (loss) of derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, attributable to parent. | 
       
       
          
          | cm:Member | 
       
       
          
          | [Member] (nonnum:domainItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | true | 
       
       
          
          | us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember |