Employee Benefit Plans - Components of Net Periodic Pension Cost (Details) - USD ($) $ in Thousands		12 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Components of net periodic pension cost
Service cost	[1]	$ 4,220	$ 4,127	$ 4,015
Interest cost		1,132	1,302	1,117
Return on plan assets		(476)	(428)	(393)
Amortization of transitional obligation		0	0	251
Amortization of prior service cost		21	26	46
Amortization of net loss		1,047	1,731	1,617
Net periodic pension cost		$ 5,944	$ 6,758	$ 6,653

[1] Service cost is reported in cost of revenues, research and development and selling, general and administrative expenses. All other components of net periodic pension cost are reported in other expense (income), net in the Consolidated Statements of Operations.