cm:Concept: us-gaap:AvailableForSaleSecuritiesEquitySecuritiesCurrent
| Available-for-sale Securities, Equity Securities, Current |
| us-gaap:AvailableForSaleSecuritiesEquitySecuritiesCurrent |
| Amount of investments in equity securities and other forms of securities that provide ownership interests classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:AvailableForSaleSecuritiesEquitySecuritiesCurrent |