cm:Level3TextBlock: us-gaap:ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock
| Reconciliation of Revenue from Segments to Consolidated [Table Text Block] |
| us-gaap:ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock |
| Tabular disclosure of all significant reconciling items in the reconciliation of total revenues from reportable segments to the entity's consolidated revenues. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock |
| ReconciliationOfRevenuefromSegmentsToConsolidated |