Retirement Benefit Plans - Net Pension Expense for Defined Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Retirement Benefits [Abstract]
Service cost	$ 174	$ 181
Interest cost	944	1,072
Expected return on plan assets	(1,057)	(1,046)
Amortization of net loss	90	143
Settlement cost	0	60
Net pension expense for defined benefit plans (non-operating expense)	$ 151	$ 410
Interest cost	Interest cost
Expected return on plan assets	Expected return on plan assets
Amortization of net loss	Amortization of net loss
Settlement cost	Settlement cost