cm:Concept: us-gaap:DeferredTaxLiabilityNotRecognizedDescriptionOfTemporaryDifferenceUndistributedEarningsOfDomesticSubsidiaries
| Deferred Tax Liability Not Recognized, Description of Temporary Difference, Undistributed Earnings of Domestic Subsidiaries |
| us-gaap:DeferredTaxLiabilityNotRecognizedDescriptionOfTemporaryDifferenceUndistributedEarningsOfDomesticSubsidiaries |
| Description of temporary difference for which a deferred tax liability has not been recognized because of the exceptions to comprehensive recognition of deferred taxes related to undistributed earnings of domestic subsidiaries. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DeferredTaxLiabilityNotRecognizedDescriptionOfTemporaryDifferenceUndistributedEarningsOfDomesticSubsidiaries |