cm:Concept: us-gaap:OptionIndexedToIssuersEquityShares
| Option Indexed to Issuer's Equity, Shares |
| us-gaap:OptionIndexedToIssuersEquityShares |
| The maximum number of shares that could be issued to net share settle a contract, if applicable. If a contract does not have a fixed or determinable maximum number of shares that may be required to be issued, disclose the fact that a potentially infinite number of shares could be issued to settle the contract. |
| cm:Concept |
| Shares (xbrli:sharesItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:OptionIndexedToIssuersEquityShares |