Stock-Based Compensation - Schedule of Additional Information of Stock-Based Compensation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding options, Weighted-average remaining contractual term (in years)	4 years 4 months 2 days	4 years 1 month 10 days
Outstanding options, Aggregate intrinsic value	$ 167,713	$ 208,152
Exercisable options, Weighted-average remaining contractual term (in years)	2 years 8 months 19 days	2 years 5 months 27 days
Exercisable options, Aggregate intrinsic value	112,724	128,150
Unrecognized compensation	$ 38,809	$ 37,397
Unrecognized compensation, Weighted average period of expected recognition (in years)	10 months 28 days	11 months 16 days