Retirement Benefit Plans - Net Pension Expense for Defined Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Retirement Benefits [Abstract]
Service cost	$ 42	$ 131
Interest cost	714	699
Expected return on plan assets	(1,362)	(1,421)
Amortization of net loss	476	846
Settlement cost	208	274
Net pension expense for defined benefit plans	$ 78	$ 529
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