cm:Concept: us-gaap:EmployeeStockOwnershipPlanESOPPlanDescription
| Employee Stock Ownership Plan (ESOP), Plan Description |
| us-gaap:EmployeeStockOwnershipPlanESOPPlanDescription |
| Description of the plan, including the basis for determining contributions, the employee groups covered, and the nature and effect of significant matters affecting comparability of information for all periods presented. For leveraged ESOPs and pension reversion ESOPs, the description generally includes the basis for releasing shares and how dividends on allocated and unallocated shares are used. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:EmployeeStockOwnershipPlanESOPPlanDescription |