cm:Concept: us-gaap:StockIssuedDuringPeriodValueDividendReinvestmentPlan
| Stock Issued During Period, Value, Dividend Reinvestment Plan |
| us-gaap:StockIssuedDuringPeriodValueDividendReinvestmentPlan |
| Value of stock issued during the period from a dividend reinvestment plan (DRIP). A dividend reinvestment plan allows the holder of the stock to reinvest dividends paid to them by the entity on new issues of stock by the entity. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:StockIssuedDuringPeriodValueDividendReinvestmentPlan |