cm:Concept: us-gaap:TranslationAdjustmentFunctionalToReportingCurrencyGainLossReclassifiedToEarningsNetOfTax
       
          
          | Translation Adjustment Functional to Reporting Currency, Gain (Loss), Reclassified to Earnings, Net of Tax | 
       
       
          
          | us-gaap:TranslationAdjustmentFunctionalToReportingCurrencyGainLossReclassifiedToEarningsNetOfTax | 
       
       
          
          | Amount of reclassification from other comprehensive income (loss) to earnings, after tax, related to translation from the functional currency to reporting currency, as a result of the sale or complete or substantially complete liquidation of an investment in a foreign entity. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Monetary (xbrli:monetaryItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | Debit | 
       
       
          
          | false | 
       
       
          
          | us-gaap:TranslationAdjustmentFunctionalToReportingCurrencyGainLossReclassifiedToEarningsNetOfTax |