Retirement Benefits (Schedule of Amount of Expense Associated with Defined Contribution Plans) (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Retirement Benefits [Abstract] | ||||
| Company costs | $ 16,198 | $ 14,032 | $ 47,444 | $ 40,002 |