CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 301,171	$ 163,671	$ 142,799
Other comprehensive income (loss):
Foreign currency translation adjustment	1,986	(2,804)	(19,961)
Effects of post-retirement adjustments, net of tax	627	184	(170)
Change in fair value of interest rate swap agreements, net of tax	7,473	14,587	(5,992)
Other comprehensive income (loss), net of tax	10,086	11,967	(26,123)
Comprehensive income	$ 311,257	$ 175,638	$ 116,676