cm:Concept: us-gaap:GoodwillTranslationAndPurchaseAccountingAdjustments
| Goodwill, Translation and Purchase Accounting Adjustments |
| us-gaap:GoodwillTranslationAndPurchaseAccountingAdjustments |
| Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:GoodwillTranslationAndPurchaseAccountingAdjustments |