Pension and Post-retirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Pension Plan
Pension Plan and Retirement Benefits
Service cost	$ 672	$ 1,182	$ 1,344	$ 2,364
Interest cost	2,772	1,923	5,544	3,846
Expected return	(3,419)	(3,561)	(6,838)	(7,122)
Amortizations	51	51	102	102
Net periodic benefit cost	76	(405)	152	(810)
Contribution to plan			3,000
Expected future employer contribution	3,000		3,000
Defined Benefit Other Postretirement Benefit Plan
Pension Plan and Retirement Benefits
Service cost	347	456	694	912
Interest cost	800	559	1,600	1,118
Amortizations	(570)	(60)	(1,140)	(120)
Net periodic benefit cost	577	$ 955	1,154	$ 1,910
Contribution to plan			1,141
Expected future employer contribution	$ 2,135		$ 2,135