Income Taxes - Summary of components of provision (benefit) for income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current provision (benefit):
Federal	$ 13,708	$ 95,995	$ (43,993)
State	3,932	13,966	(24,479)
Foreign	6,843	2,953	4,567
Deferred provision (benefit):
Federal	23,203	(39,710)	(31,505)
State	(1,808)	(2,899)	(2,704)
Total income tax provision (benefit)	$ 45,878	$ 70,305	$ (98,114)