Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Retirement Benefits [Abstract]
Service cost	$ 6	$ 10	$ 18	$ 31
Interest cost	274	178	824	535
Expected return on plan assets	(277)	(340)	(831)	(1,021)
Amortization of net loss	77	119	230	357
Settlement cost	78	69	78	69
Net periodic pension cost (benefit)	$ 158	$ 36	$ 319	$ (29)