Earnings Per Share - Schedule of Dilutive Effect of Stock Options RSUs and PSAs (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net Income	$ 15,318	$ 12,417
Weighted-average number of basic shares outstanding during the period	18,825	18,670
Dilutive effect of stock options, RSUs, and performance shares	438	488
Weighted-average number of diluted shares outstanding during the period	19,263	19,158
Basic earnings per share	$ 0.81	$ 0.67
Diluted earnings per share	$ 0.80	$ 0.65