Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding - January 1, 2015, Options		1,859,350
Granted, Options		2,000
Exercised, Options		(99,050)	(185,000)
Forfeited, Options		(74,350)
Outstanding - June 30, 2015, Options		1,687,950
Fully vested and exercisable - June 30, 2015, Options		315,550
Expected to vest in future periods, Options		1,248,680
Fully vested and expected to vest - June 30, 2015, Options	[1]	1,564,230
Outstanding - January 1, 2015, Weighted-Average Exercise Price/Share		$ 23.49
Granted, Weighted-Average Exercise Price/Share		40.82
Exercised, Weighted-Average Exercise Price/Share		10.06
Forfeited, Weighted-Average Exercise Price/Share		26.13
Outstanding - June 30, 2015, Weighted-Average Exercise Price/Share		24.18
Fully vested and exercisable - June 30, 2015, Weighted-Average Exercise Price/Share		14.17
Fully vested and expected to vest - June 30, 2015, Weighted-Average Exercise Price/Share	[1]	$ 23.58
Outstanding - June 30, 2015, Weighted-Average Remaining Contractual Life (in years)		5 years 3 months 18 days
Fully vested and exercisable - June 30, 2015, Weighted-Average Remaining Contractual Life (in years)		4 years 7 months 6 days
Fully vested and expected to vest - June 30, 2015, Weighted-Average Remaining Contractual Life (in years)		5 years 2 months 12 days
Outstanding - June 30, 2015, Aggregate Intrinsic Value	[2]	$ 36,400
Fully vested and exercisable - June 30, 2015, Aggregate Intrinsic Value	[2]	9,966
Fully vested and expected to vest - June 30, 2015, Aggregate Intrinsic Value	[2]	$ 34,676

[1] At June 30, 2015, the Company estimated that outstanding options to purchase 123,720 shares of its common stock would not vest and would be forfeited prior to their vesting date.

[2] Based on closing price of $45.75 per share on June 30, 2015.