Earnings Per Share - Components of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 35,825						$ 61,021	$ 40,496
Net loss attributable to redeemable noncontrolling interest	259						865
Net income	$ 36,084	$ 16,995	$ 8,807	$ 17,690	$ 13,796	$ 9,010	$ 61,886	40,496
Net income attributable to common stockholders				$ 17,690				$ 40,496
Weighted average common shares outstanding - basic (in shares)	49,007,343			48,518,041			48,842,333	48,360,927
Dilutive effect of stock options and restricted stock units (in shares)	1,972,336			1,634,766			1,831,419	1,877,482
Weighted average common shares outstanding - diluted (in shares)	50,979,679			50,152,807			50,673,752	50,238,409
Weighted average common shares outstanding — diluted (C)
Basic (in dollars per share)	$ 0.74			$ 0.36			$ 1.27	$ 0.84
Diluted (in dollars per share)	$ 0.71			$ 0.35			$ 1.22	$ 0.81