Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares, Outstanding at December 31, 2013	1,734
Number of Shares, Granted	532
Number of Shares, Exercised	(182)
Number of Shares, Forfeited	(65)
Number of Shares, Outstanding at September 30, 2014	2,019
Number of Shares, Exercisable at September 30, 2014	898
Weighted - Average Exercise Price Per Share, Outstanding, Beginning balance	$ 31.85
Weighted - Average Exercise Price Per Share, Granted	$ 38.12
Weighted - Average Exercise Price Per Share, Exercised	$ 29.89
Weighted - Average Exercise Price Per Share, Forfeited	$ 34.69
Weighted - Average Exercise Price Per Share, Outstanding, Ending balance	$ 33.59
Weighted - Average Exercise Price Per Share, Exercisable at September, 2014	$ 30.29
Weighted - Average Remaining Contractual Term, Outstanding at September 30, 2014	7 years 2 months 23 days
Weighted - Average Remaining Contractual Term, Exercisable at September 30, 2014	5 years 1 month 13 days
Aggregate Intrinsic Value, Outstanding at September 30, 2014	$ 7,452
Aggregate Intrinsic Value, Exercisable at September 30, 2014	$ 5,977