Pension and Post-retirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Pension Plan
Pension Plan and Retirement Benefits
Service cost	$ 1,182	$ 1,407	$ 3,546	$ 4,221
Interest cost	1,923	1,808	5,769	5,424
Expected return	(3,561)	(3,978)	(10,683)	(11,934)
Amortizations	51	1,956	153	5,868
Net periodic benefit cost	(405)	1,193	(1,215)	3,579
Contribution to plan			4,500
Expected future employer contribution	1,500		1,500
Defined Benefit Other Postretirement Benefit Plan
Pension Plan and Retirement Benefits
Service cost	456	274	1,368	822
Interest cost	559	572	1,677	1,718
Amortizations	(60)		(180)
Net periodic benefit cost	955	$ 846	2,865	$ 2,540
Contribution to plan			2,018
Expected future employer contribution	$ 1,441		$ 1,441