Retirement Benefits - Summary of other postretirement benefit plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Amounts recognized on the Consolidated Balance Sheet
Pensions and other postretirement benefits	$ (437,490)	$ (551,510)
Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	78,567	48,876
Service cost	279	330
Interest cost	3,571	3,004
Acquisition	0	39,112
Actuarial gain	(3,952)	(4,403)
Benefits paid	(7,057)	(8,352)
Benefit obligation at end of year	71,408	78,567
Funded status	(71,408)	(78,567)
Amounts recognized on the Consolidated Balance Sheet
Other accrued liabilities	(7,173)	(7,831)
Pensions and other postretirement benefits	(64,235)	(70,736)
Net amount recognized	(71,408)	(78,567)
Amounts recognized in Accumulated Other Comprehensive (Loss)
Net actuarial gain	$ (20,155)	$ (17,952)