cm:Concept: us-gaap:ProceedsFromIssuanceOfPreferredStockAndPreferenceStock
| Proceeds from Issuance of Preferred Stock and Preference Stock |
| us-gaap:ProceedsFromIssuanceOfPreferredStockAndPreferenceStock |
| Proceeds from issuance of capital stock which provides for a specific dividend that is paid to the shareholders before any dividends to common stockholders and which takes precedence over common stockholders in the event of liquidation. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:ProceedsFromIssuanceOfPreferredStockAndPreferenceStock |