cm:Level1TextBlock: us-gaap:Reclassifications
| Reclassifications [Text Block] |
| us-gaap:Reclassifications |
| The entire disclosure for classifying current financial statements, which may be different from classifications in the prior year's financial statements. Disclose any material changes in classification including an explanation of the reason for the change and the areas impacted. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:Reclassifications |
| ReclassificationsDisclosure |