cm:Concept: us-gaap:OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax
| Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax |
| us-gaap:OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax |
| Amount of tax expense (benefit), before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax |