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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings (numerator)
Net income attributable to common stockholders	$ 14,450	$ 10,648	$ 28,846	$ 14,667
Shares (denominator)
Weighted average common shares outstanding (basic)	49,057	48,814	48,633	48,496
Dilutive effect of stock options and stock awards outstanding	1,359	1,108	1,428	1,069
Adjusted weighted average common shares outstanding (diluted)	50,416	49,922	50,061	49,565
Earnings per share attributable to common stockholders
Basic	$ 0.29	$ 0.22	$ 0.59	$ 0.30
Diluted	$ 0.29	$ 0.21	$ 0.58	$ 0.30