cm:Concept: us-gaap:DifferenceBetweenReportedAmountAndReportingCurrencyDenominatedAmountValue
| Difference between Reported Amount and Reporting Currency Denominated Amount, Value |
| us-gaap:DifferenceBetweenReportedAmountAndReportingCurrencyDenominatedAmountValue |
| The amount of difference between the reported amount and the reporting currency-denominated amount. The default debit balance is based on the reported amount that is greater that the reporting currency-denominated amount. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:DifferenceBetweenReportedAmountAndReportingCurrencyDenominatedAmountValue |