Income Taxes - Provision (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
(Loss) before income taxes	$ (110,117)	$ (104,256)	$ (190,878)	$ (140,283)
Income tax provision (benefit)	1,482	(16,272)	2,902	(23,552)
NET (LOSS)	$ (111,599)	$ (87,984)	$ (193,780)	$ (116,731)
Income tax provision (benefit) as a percentage of (loss) before income taxes	(1.30%)	15.60%	(1.50%)	16.80%