cm:Concept: us-gaap:DeferredTaxesBusinessCombinationValuationAllowanceAvailableToReduceIntangibleAssets
| Deferred Taxes, Business Combination, Valuation Allowance, Available to Reduce Intangible Assets |
| us-gaap:DeferredTaxesBusinessCombinationValuationAllowanceAvailableToReduceIntangibleAssets |
| The amount of the valuation allowance recorded in a business combination against deductible temporary differences for which related tax benefits will be recorded as a reduction of the acquired entity's other noncurrent intangible assets if those tax benefits subsequently become realizable. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:DeferredTaxesBusinessCombinationValuationAllowanceAvailableToReduceIntangibleAssets |