cm:Level3TextBlock: us-gaap:ScheduleOfUnusualOrInfrequentItemsTextBlock
| Schedule of Unusual or Infrequent Items, or Both [Table Text Block] |
| us-gaap:ScheduleOfUnusualOrInfrequentItemsTextBlock |
| Tabular disclosure of the nature and financial statement effect of an event or transaction that is unusual in nature or infrequent in occurrence, or both. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ScheduleOfUnusualOrInfrequentItemsTextBlock |
| UnusualOrInfrequentItem |