Employee Benefits and Share-Based Compensation - Stock Option Activity (Details) - 2009 Plan - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Number of Shares
Outstanding at December 31, 2015 (in shares)	2,688
Granted (in shares)	376
Exercised (in shares)	(49)
Expired (in shares)	(1)
Forfeited (in shares)	(38)
Outstanding at March 31, 2016 (in shares)	2,976		2,688
Exercisable at March 31, 2016 (in shares)	1,478
Vested and expected to vest at March 31, 2016 (in shares)	2,790
Weighted Average Exercise Price
Outstanding at December 31, 2015 (in dollars per share)	$ 22.89
Granted (in dollars per share)	27.75
Exercised (in dollars per share)	13.48
Expired (in dollars per share)	19.96
Forfeited (in dollars per share)	28.51
Outstanding at March 31, 2016 (in dollars per share)	23.59		$ 22.89
Exercisable at March 31, 2016 (in dollars per share)	18.53
Vested and expected to vest at March 31, 2016 (in dollars per share)	$ 23.23
Weighted-average remaining years, outstanding (in years)	7 years 1 day		6 years 10 months 20 days
Weighted-average remaining years, exercisable at March 31, 2016 (in years)	5 years
Weighted-average remaining years, vested and expected to vest at March 31, 2016 (in years)	6 years 10 months 24 days
Aggregate Intrinsic Value, outstanding at March 31, 2016	$ 15,891
Aggregate Intrinsic Value, exercisable at March 31, 2016	14,329
Aggregate Intrinsic Value, vested and expected to vest at March 31, 2016	$ 15,806
Employee Stock Option
Weighted Average Exercise Price
Weighted-average fair value (in dollars per share)	$ 8.51	$ 9.82
Intrinsic value of options exercised	$ 700	$ 2,400
Unrecognized compensation cost of unvested stock options	$ 11,300
Weighted average period of compensation cost recognized	3 years 20 days