Benefit Plans - Qualified and Non-Qualified Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income or Loss (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation And Retirement Disclosure [Abstract]
Net (gain) loss	$ (37,955)	$ 11,747
Prior service cost	119	944	244
Recognized prior service cost	(2,386)	(873)
Amortization of actuarial loss	(1,970)	(2,401)	(1,540)
Total recognized in other comprehensive income	(42,192)	9,417
Total recognized in net periodic pension expense and other comprehensive income (before tax)	$ (36,840)	$ 17,608	$ 1,540