cm:Level1TextBlock: us-gaap:BusinessCombinationDisclosureTextBlock
| Business Combination Disclosure [Text Block] |
| us-gaap:BusinessCombinationDisclosureTextBlock |
| The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable). |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:BusinessCombinationDisclosureTextBlock |
| BusinessCombinationDisclosure |