Stock-Based Compensation - Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Number of Options
Outstanding at December 31, 2014 | shares	650
Granted | shares	74
Exercised | shares	(69)
Forfeited/canceled/expired | shares	(8)
Outstanding at September 30, 2015 | shares	647
Vested and expected to vest at September 30, 2015 | shares	647
Exercisable on September 30, 2015 | shares	471
Weighted-Average Exercise Price
Outstanding at December 31, 2014	$ 25.56
Granted	65.54
Exercised	23.95
Forfeited/canceled/expired	20.64
Outstanding at September 30, 2015	30.35
Vested and expected to vest at September 30, 2015	30.35
Exercisable on September 30, 2015	$ 24.96
Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value
Outstanding at September 30, 2015	5 years 25 days
Vested and expected to vest at September 30, 2015	5 years 25 days
Exercisable on September 30, 2015	4 years 7 months 24 days
Exercised | $	$ 2,122
Outstanding at September 30, 2015 | $	9,286	[1]
Vested and expected to vest at September 30, 2015 | $	9,282	[1]
Exercisable on September 30, 2015 | $	$ 8,034	[1]

[1] The aggregate intrinsic value represents the total pre-tax value (the difference between our closing stock price on the last trading day of the third quarter of 2015 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had they all exercised their options on September 30, 2015. This amount will change based on the fair market value of our stock.