Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Compensation And Retirement Disclosure [Abstract]
Service costs	$ 390	$ 329	$ 1,170	$ 986
Interest costs	6,786	7,933	20,805	21,845
Expected return on plan assets	(5,341)	(6,165)	(16,237)	(15,554)
Amortization of net actuarial loss	7,613	2,372	24,596	17,186
Amortization of prior service credit	(1,041)	(1,038)	(3,122)	(3,115)
Net periodic cost	$ 8,407	$ 3,431	$ 27,212	$ 21,348