Pension Plans - Components of Net Periodic Pension Cost (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Interest cost of projected benefit obligation	$ 2,121	$ 2,368	$ 2,126
Service cost	578	674	690
Expected return on plan assets	(3,700)	(3,361)	(3,541)
Amortization of prior service cost	0	0	0
Recognized actuarial loss	697	398	241
Settlement gain	(65)	(19)	0
Net periodic pension (benefit) cost	$ (369)	$ 60	$ (484)