Schedule of Net Periodic Pension Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Service cost	$ 912	$ 967	$ 2,803	$ 2,865
Interest cost	133	109	409	323
Expected return on plan assets	(239)	(218)	(735)	(646)
Net amortization	37	(150)	(5)
Net periodic pension costs	$ 843	$ 708	$ 2,472	$ 2,542