Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Service costs	$ 184	$ 261
Interest costs	4,641	5,964
Expected return on plan assets	(2,370)	(3,094)
Amortization of net actuarial loss	6,933	7,037
Amortization of prior service credit	(1,211)	(1,211)
Net periodic cost	$ 8,177	$ 8,957