Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerators:
Net income	$ 16,788	$ 13,820
Denominators:
Basic weighted average common shares outstanding (in shares)	33,845,560	33,380,028
Dilutive effect of share based awards (in shares)	1,263,322	971,629
Diluted weighted average common shares outstanding (in shares)	35,108,882	34,351,657
Earnings Per Share:
Basic (in dollars per share)	$ 0.50	$ 0.41
Diluted (in dollars per share)	$ 0.48	$ 0.40
Weighted average common shares considered anti-dilutive in computing diluted earnings per share (in shares)	452,988	200,752