Income Taxes - Reconciliation of income tax expense (benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Federal income tax expense	$ (96,092)	$ 20,773	$ 10,005
State income tax expense, net of federal benefit	(17,089)	4,133	952
Non-deductible equity-based compensation	13,694	8,087	13,296
Non-deductible IPO expenses		1	1,948
Charitable contributions	(2,473)
Other	(506)	(683)	60
Total income tax expense	$ (102,466)	$ 32,311	$ 26,261