cm:Concept: us-gaap:RevenuePerformanceObligationDescriptionOfReturnsAndOtherSimilarObligations
| Revenue, Performance Obligation, Description of Returns and Other Similar Obligations |
| us-gaap:RevenuePerformanceObligationDescriptionOfReturnsAndOtherSimilarObligations |
| Description of obligation for returns, refunds, and other similar obligations in contract with customer. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:RevenuePerformanceObligationDescriptionOfReturnsAndOtherSimilarObligations |