cm:Level1TextBlock: us-gaap:NewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock
| New Accounting Pronouncements and Changes in Accounting Principles [Text Block] |
| us-gaap:NewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock |
| The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:NewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock |
| NewAccountingPronouncementsOrChangeInAccountingPrinciple |