cm:Concept: us-gaap:SaleOfStockDescriptionOfTransaction
| Sale of Stock, Description of Transaction |
| us-gaap:SaleOfStockDescriptionOfTransaction |
| Description of stock transaction which may include details of the offering (IPO, private placement), a description of the stock sold, percentage of subsidiary's or equity investee's stock sold, a description of the investors and whether the stock was issued in a business combination. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:SaleOfStockDescriptionOfTransaction |