cm:Concept: us-gaap:RevenueInitialApplicationPeriodCumulativeEffectTransitionExplanationOfChange
| Revenue, Initial Application Period Cumulative Effect Transition, Explanation of Change |
| us-gaap:RevenueInitialApplicationPeriodCumulativeEffectTransitionExplanationOfChange |
| Description of reason for change from application of new guidance compared to guidance in effect prior to change when using transition method for cumulative effect in initial period of application for revenue from contract with customer. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:RevenueInitialApplicationPeriodCumulativeEffectTransitionExplanationOfChange |