cm:Concept: us-gaap:NonmonetaryTransactionGainLossRecognizedOnTransfer
| Nonmonetary Transaction, Gain (Loss) Recognized on Transfer |
| us-gaap:NonmonetaryTransactionGainLossRecognizedOnTransfer |
| Disclosure of the difference in values (gain (loss)) between the nonmonetary assets or liabilities exchanged with another entity inclusive of boot (small monetary consideration). |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:NonmonetaryTransactionGainLossRecognizedOnTransfer |