cm:Concept: us-gaap:EmployeeStockOwnershipPlanESOPNumberOfSuspenseShares
| Employee Stock Ownership Plan (ESOP), Number of Suspense Shares |
| us-gaap:EmployeeStockOwnershipPlanESOPNumberOfSuspenseShares |
| Shares contributed to the ESOP that have not yet been released, committed to be released, or allocated to participant accounts. Suspense shares generally collateralize ESOP debt. |
| cm:Concept |
| Shares (xbrli:sharesItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:EmployeeStockOwnershipPlanESOPNumberOfSuspenseShares |