Pension and Post-retirement Benefits - Net Periodic Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0
Interest cost	1,113	1,349
Expected return on plan assets	(1,108)	(1,294)
Amortization of net loss	13	10
Total	18	65
Post Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	21	18
Interest cost	51	60
Amortization of prior service credit	(134)	(134)
Amortization of net loss	42	21
Total	$ (20)	$ (35)