Changes in Accumulated Other Comprehensive Income ("AOCI") by Component, Net of Tax (Detail) $ in Thousands	9 Months Ended
	Mar. 31, 2019 USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 1,024,311
Other comprehensive income before reclassifications	(6,425)
Amounts reclassified from AOCI	(4)
Net current-period other comprehensive income	(6,429)
Ending Balance	1,113,558
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,308)
Other comprehensive income before reclassifications	(6,425)
Net current-period other comprehensive income	(6,425)
Ending Balance	(7,733)
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(2,472)
Amounts reclassified from AOCI	(4)
Net current-period other comprehensive income	(4)
Ending Balance	(2,476)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(3,780)
Ending Balance	$ (10,209)