Changes in Accumulated Other Comprehensive Income ("AOCI") by Component, Net of Tax (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 782,338	$ 729,081	$ 675,043
Other comprehensive income (loss) before reclassifications	(355)	(22,456)	(10,741)
Amounts reclassified from AOCI	594	(226)
Net current-period other comprehensive income	239	(22,682)	(10,741)
Ending Balance	900,563	782,338	729,081
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(6,185)	9,466	17,963
Other comprehensive income (loss) before reclassifications	(2,275)	(15,651)	(8,497)
Net current-period other comprehensive income	(2,275)	(15,651)	(8,497)
Ending Balance	(8,460)	(6,185)	9,466
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(7,832)	(801)	1,443
Other comprehensive income (loss) before reclassifications	1,920	(6,805)	(2,244)
Amounts reclassified from AOCI	594	(226)
Net current-period other comprehensive income	2,514	(7,031)	(2,244)
Ending Balance	(5,318)	(7,832)	(801)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(14,017)	8,665	19,406
Ending Balance	$ (13,778)	$ (14,017)	$ 8,665