Stock-Based Compensation Plans - Additional Information 3 (Detail) (USD $) In Thousands, except Share data in Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Non-cash, Mark-to-market (income) loss related to deferred compensation plan	$ (46,198)	$ (2,225)	$ (37,714)	$ 33,257
Shares held in rabbi trust total	2.8		2.8		2.8
Vested shares held in rabbi trust	2.4		2.4		2.4