Pension and Post-retirement Benefits - Net Periodic Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,537	$ 1,464	$ 4,591	$ 4,354
Expected return on plan assets	(1,084)	(1,015)	(3,231)	(3,007)
Amortization of net loss	10	10	30	30
Total	463	459	1,390	1,377
Post Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	6	14	17
Interest cost	17	18	52	53
Amortization of prior service credit	(369)	(369)	(1,106)	(1,106)
Amortization of net loss	30	44	92	133
Total	$ (317)	$ (301)	$ (948)	$ (903)