Stockholders' Equity - Summary of Stock Option Activity (Detail) - Jun. 30, 2015 - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Total
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding at December 31, 2014	1,954
Number of Shares, Granted	52
Number of Shares, Exercised	(43)
Number of Shares, Forfeited	(70)
Number of Shares, Outstanding at June 30, 2015	1,893
Number of Shares, Exercisable at June 30, 2015	1,026
Number of Shares, Vested and expected to vest at June 30, 2015	1,807
Weighted - Average Exercise Price Per Share, Outstanding, Beginning balance	$ 33.81
Weighted - Average Exercise Price Per Share, Granted	38.11
Weighted - Average Exercise Price Per Share, Exercised	29.70
Weighted - Average Exercise Price Per Share, Forfeited	36.59
Weighted - Average Exercise Price Per Share, Outstanding, Ending balance	33.92
Weighted - Average Exercise Price Per Share, Exercisable at June 30, 2015	31.42
Weighted Average Exercise Price Per Share, Vested and expected to vest at June 30, 2015	$ 33.76
Weighted - Average Remaining Contractual Term, Outstanding at June 30, 2015	6 years 7 months 28 days
Weighted - Average Remaining Contractual Term, Exercisable at June 30, 2015	5 years 26 days
Weighted - Average Remaining Contractual Term, Vested and expected to vest at June 30, 2015	6 years 6 months 22 days
Aggregate Intrinsic Value, Outstanding at June 30, 2015	$ 5,516
Aggregate Intrinsic Value, Exercisable at June 30, 2015	4,940
Aggregate Intrinsic Value, Vested and expected to vest at June 30, 2015	$ 5,477