Stock-Based Compensation Plans - Additional Information 3 (Detail) - USD ($) $ in Thousands, shares in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Deferred compensation plan vesting period	3 years
Deferred compensation plan	$ 16,056	$ (5,624)
Shares held in rabbi trust total	2.8		2.8
Vested shares held in rabbi trust	2.4		2.5