Pension and Other Postretirement Benefits - Components of Net Periodic Other Postretirement Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Net periodic other postretirement benefit costs
Special termination benefit charge		$ 277
Other postretirement benefit plans [Member]
Net periodic other postretirement benefit costs
Interest cost	$ 417	288	$ 307
Amortization of prior service credit	(271)	(276)	(276)
Recognition of actuarial loss	192	297	307
Net Periodic Benefit (Income) Cost	338	309	338
Pension Plan [Member]
Net periodic other postretirement benefit costs
Service cost	963	1,117	1,685
Interest cost	32,235	22,532	23,188
Amortization of prior service credit	5	13	34
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	(1)	(2)	(7)
Recognition of actuarial loss	4,440	11,702	13,606
Special termination benefit charge	431		(473)
Net Periodic Benefit (Income) Cost	$ (1,950)	$ (15,990)	$ (12,336)