Employee Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Loss) Income (Detail) (Pension Benefits [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current year actuarial (gain) loss	$ (368,587)	$ 114,061	$ 311,038
Recognition of actuarial loss	(83,934)	(70,161)	(53,039)
Current year prior service credit		(4,217)
Recognition of prior service credit	7,538	30,777	6,970
Total recognized in other comprehensive (loss) income	(444,983)	70,460	264,969
Total recognized in net periodic benefit cost and other comprehensive (loss) income	$ (393,912)	$ 97,228	$ 297,220