Earnings (Loss) per Common Share - Basic Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic earnings (loss) per Class A common share
Net (loss) income	$ (2,992)	$ (531)	$ 47,147	$ 98,204
Net (loss) income allocated to Class A common stockholders	$ (2,949)	$ (531)	$ 46,405	$ 98,204
Basic weighted-average common shares issued and outstanding (in shares)	52,635	51,595	52,269	52,405
Basic (loss) earnings per common share (in usd per share)	$ (0.06)	$ (0.01)	$ 0.89	$ 1.87
Diluted earnings (loss) per Class A common share
Net (loss) income allocated to Class A common stockholders	$ (2,949)	$ (531)	$ 46,405	$ 98,204
Re-allocated earnings	(1)	0	16	0
Diluted net (loss) income allocated to Class A common stockholders	$ (2,950)	$ (531)	$ 46,421	$ 98,204
Basic weighted-average common shares issued and outstanding (in shares)	52,635	51,595	52,269	52,405
Diluted weighted-average Class A shares issued and outstanding (in shares)	54,082	52,295	53,455	53,474
Diluted (loss) earnings per common share (in usd per share)	$ (0.06)	$ (0.01)	$ 0.87	$ 1.84
Other Classes of Common Stock
Basic earnings (loss) per Class A common share
Net (loss) income allocated to Class A common stockholders	$ 43	$ 0	$ (742)	$ 0
Diluted earnings (loss) per Class A common share
Net (loss) income allocated to Class A common stockholders	43	0	(742)	0
Common Class A
Basic earnings (loss) per Class A common share
Net (loss) income allocated to Class A common stockholders	(2,949)	(531)	46,405	98,204
Diluted earnings (loss) per Class A common share
Net (loss) income allocated to Class A common stockholders	$ (2,949)	$ (531)	$ 46,405	$ 98,204
Stock options
Diluted earnings (loss) per Class A common share
Dilutive potential common shares (in shares)	426	83	208	130
Restricted stock units
Diluted earnings (loss) per Class A common share
Dilutive potential common shares (in shares)	751	199	658	463
Performance-based restricted stock units
Diluted earnings (loss) per Class A common share
Dilutive potential common shares (in shares)	231	373	298	413
Employee stock purchase plan
Diluted earnings (loss) per Class A common share
Dilutive potential common shares (in shares)	39	45	22	63