cm:Level3TextBlock: us-gaap:SummaryOfPositionsForWhichSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTextBlock
| Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table Text Block] |
| us-gaap:SummaryOfPositionsForWhichSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTextBlock |
| Tabular disclosure of unrecognized tax benefits for which a material change is reasonably possible in the next twelve months, typically including the nature of the uncertainty, the event(s) that could cause a material change, and an estimate of the range of the reasonably possible change or a statement that an estimate of the range cannot be made. An unrecognized tax benefit is the difference between a tax position taken in a tax return and the amounts recognized in the financial statements for which it is more likely than not, based on the technical merits of the position, that the tax position will not be sustained upon examination. |
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| us-gaap:SummaryOfPositionsForWhichSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTextBlock |
| SignificantChangeInUnrecognizedTaxBenefitsisReasonablyPossible |