Net Periodic Benefit Cost (Detail) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Components of net periodic benefit costs:
Service cost	$ 924	$ 673	$ 2,865	$ 2,569
Interest cost	4,837	3,578	15,419	16,987
Expected return on plan assets	(5,745)	(4,598)	(18,315)	(19,670)
Net periodic cost (benefit)	$ 16	$ (347)	$ (31)	$ (114)