cm:Level1TextBlock: us-gaap:NonmonetaryTransactionsDisclosureTextBlock
| Nonmonetary Transactions Disclosure [Text Block] |
| us-gaap:NonmonetaryTransactionsDisclosureTextBlock |
| The entire disclosure for exchanges with other entities that involve principally nonmonetary assets or liabilities or relate to a transfer of nonmonetary assets for which the entity receives no assets in return. |
| cm:Level1TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:NonmonetaryTransactionsDisclosureTextBlock |
| NonmonetaryTransactionsDisclosure |