cm:LineItems: us-gaap:SubsequentEventLineItems
| Subsequent Event [Line Items] |
| us-gaap:SubsequentEventLineItems |
| Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. |
| cm:LineItems |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:SubsequentEventLineItems |