Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation And Retirement Disclosure [Abstract]
Service costs	$ 1,560	$ 1,315	$ 1,915
Interest costs	27,744	29,180	26,861
Expected return on plan assets	(21,802)	(20,850)	(18,776)
Amortization of net actuarial loss	32,645	22,587	32,033
Amortization of prior service credit	(4,163)	(4,153)	(4,385)
Net periodic cost	$ 35,984	$ 28,079	$ 37,648