Stock-Based Compensation Plans - Additional Information 3 (Detail) (USD $) In Thousands, except Share data in Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-cash, Mark-to-market income (loss) related to deferred compensation plan	$ 10,519	$ (6,878)	$ 8,484	$ 35,482
Shares held in rabbi trust total	2.9		2.9		2.8
Vested shares held in rabbi trust	2.4		2.4		2.4