Pension and Other Postretirement Benefits - Components of Net Periodic Other Postretirement Benefit Cost (Details) - Other postretirement benefit plans [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Net periodic other postretirement benefit costs
Interest cost	$ 72	$ 76	$ 144	$ 153
Amortization of prior service credit	(69)	(69)	(138)	(138)
Recognition of actuarial loss	74	77	148	154
Net periodic other postretirement benefit cost	$ 77	$ 84	$ 154	$ 169