Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings (numerator)
Net income attributable to common stockholders	$ 36,284	$ 25,068	$ 68,000	$ 43,594
Shares (denominator)
Weighted average common shares outstanding (basic)	50,658	49,680	50,529	49,509
Dilutive effect of stock options and stock awards outstanding	962	1,112	1,037	1,218
Adjusted weighted average common shares outstanding (diluted)	51,620	50,792	51,566	50,727
Earnings per share attributable to common stockholders
Basic	$ 0.72	$ 0.50	$ 1.35	$ 0.88
Diluted	$ 0.70	$ 0.49	$ 1.32	$ 0.86
Stock options and stock awards excluded from EPS calculation because the effect would be anti-dilutive	131	24	95	13