cm:Concept: us-gaap:DescriptionOfAccountingMethodForInterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstruments
| Description of Accounting Method for Interest Rate Derivative Instruments Not Designated as Hedging Instruments |
| us-gaap:DescriptionOfAccountingMethodForInterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstruments |
| General discussion of the accounting for interest rate derivatives not designated as hedging instruments. Includes discussion of where derivatives and the gain (loss) on derivatives are reported in the financial statements. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DescriptionOfAccountingMethodForInterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstruments |