Schedule of Net Periodic Pension Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Service cost	$ 946	$ 871	$ 1,898	$ 1,768
Interest cost	107	38	214	78
Expected return on plan assets	(213)	(175)	(428)	(356)
Net amortization	45	561	150	397
Net periodic pension costs	$ 885	$ 1,295	$ 1,834	$ 1,887