Changes in Accumulated Other Comprehensive Income ("AOCI") by Component, Net of Tax (Detail) $ in Thousands	3 Months Ended
	Sep. 30, 2018 USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 1,024,311
Other comprehensive income before reclassifications	(10,651)
Amounts reclassified from AOCI	52
Net current-period other comprehensive income	(10,599)
Ending Balance	1,043,588
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,308)
Other comprehensive income before reclassifications	(10,651)
Net current-period other comprehensive income	(10,651)
Ending Balance	(11,959)
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(2,472)
Amounts reclassified from AOCI	52
Net current-period other comprehensive income	52
Ending Balance	(2,420)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(3,780)
Ending Balance	$ (14,379)