Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Compensation And Retirement Disclosure [Abstract]
Service costs	$ 260	$ 390	$ 781	$ 1,170
Interest costs	5,999	6,786	18,000	20,805
Expected return on plan assets	(3,083)	(5,341)	(9,250)	(16,237)
Amortization of net actuarial loss	7,043	7,613	21,153	24,596
Amortization of prior service credit	(1,211)	(1,041)	(3,633)	(3,122)
Net periodic cost	$ 9,008	$ 8,407	$ 27,051	$ 27,212