cm:Concept: us-gaap:DerivativesBasisAndUseOfDerivativesBasisDeterminationOfFairValue
| Derivatives, Determination of Fair Value |
| us-gaap:DerivativesBasisAndUseOfDerivativesBasisDeterminationOfFairValue |
| Describes how an entity determines the fair values of its derivatives, including its valuation methodology and significant assumptions used. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DerivativesBasisAndUseOfDerivativesBasisDeterminationOfFairValue |