Stock-Based Compensation - Summary of Share-Based Option Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Outstanding, Beginning of Period	8,463,811
Shares Granted	0
Shares Exercised	(77,527)
Shares Canceled	(16,784)
Shares Expired	(3,830)
Shares Outstanding, End of Period	8,365,670
Shares Vested and expected to vest at March 31, 2014	8,033,454
Shares Exercisable at March 31, 2014	2,966,899
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price Outstanding, Beginning of Period	$ 12.09
Weighted Average Exercise Price Granted	$ 0.00
Weighted Average Exercise Price Exercised	$ 11.53
Weighted Average Exercise Price Canceled	$ 8.89
Weighted Average Exercise Price Expired	$ 14.73
Weighted Average Exercise Price Outstanding, End of Period	$ 12.08
Weighted Average Exercise Price Vested and expected to vest at March 31, 2014	$ 11.89
Weighted Average Exercise Price Exercisable at March 31, 2014	$ 14.02