Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 7,187	$ 17,369	$ 37,014	$ 33,713
Basic earnings per share - weighted average shares outstanding	31,901	31,571	31,807	31,455
Employee stock options and restricted stock units - dilutive shares	507	599	580	669
Warrant - dilutive shares	0	0	0	2
Diluted earnings per share - weighted average shares outstanding	32,408	32,170	32,387	32,126
Basic	$ 0.23	$ 0.55	$ 1.16	$ 1.07
Diluted	$ 0.22	$ 0.54	$ 1.14	$ 1.05