Pension and Post-retirement Benefits - Net Periodic Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,502	$ 1,408	$ 3,054	$ 2,890
Expected return on plan assets	(1,049)	(960)	(2,147)	(1,992)
Amortization of net loss	10	10	20	20
Total net (benefit)	463	458	927	918
Post Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5	9	11
Interest cost	18	17	35	35
Amortization of prior service credit	(368)	(368)	(737)	(737)
Amortization of net loss	31	45	62	89
Total net (benefit)	$ (315)	$ (301)	$ (631)	$ (602)