Stock-based Compensation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Shares
Outstanding at December 31, 2014	5,571
Granted	745
Exercised	(1,182)
Forfeited	(386)
Outstanding at December 31, 2015	4,748	5,571
Exercisable at December 31, 2014	3,621
Vested and expected to vest at December 31, 2015	4,691
Weighted-Average Exercise Price
Outstanding at December 31, 2014	$ 25.14
Granted	30.82
Exercised	17.67
Forfeited	30.83
Outstanding at December 31, 2015	27.49	$ 25.14
Exercisable at December 31, 2015	26.58
Vested and expected to vest at December 31, 2015	$ 27.45
Weighted-Average Remaining Contractual Term (in years)
Outstanding at December 31, 2014	5 years 6 months	5 years
Exercisable at December 31, 2015	4 years 6 months
Vested and expected to vest at December 31, 2015	5 years 6 months
Outstanding at December 31, 2015	5 years 6 months	5 years
Aggregate Intrinsic Value
Outstanding at December 31, 2015	$ 13,475
Exercisable at December 31, 2015	12,631
Vested and expected to vest at December 31, 2015	$ 13,433