Stock Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Options Granted
Outstanding at beginning of period	2,716,834	2,769,616	2,861,934
Options granted		23,000	142,750
Options exercised	(690,592)	(62,614)	(169,732)
Options forfeited	(53,358)	(13,168)	(65,336)
Outstanding at end of period	1,972,884	2,716,834	2,769,616
Options exercisable	1,945,032	2,599,010	2,558,184
Weighted Average Exercise Price
Outstanding at beginning of period	$ 6.35	$ 6.34	$ 6.19
Options granted		9.88	9.04
Options exercised	6.17	6.47	5.60
Options forfeited	9.18	8.24	7.64
Outstanding at end of period	6.34	6.35	6.34
Options exercisable	$ 6.30	$ 6.23	$ 6.16
Weighted-Average Remaining Contractual Term
Outstanding at end of period	2 years 5 months 12 days	3 years 6 months 7 days	4 years 6 months
Options exercisable	2 years 4 months 21 days	3 years 3 months 18 days	4 years 1 month 24 days
Aggregate Intrinsic Value
Outstanding at end of period	$ 15,601	$ 14,782	$ 7,378
Options exercisable	$ 15,457	$ 14,463	$ 7,272