Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Consolidated Statement of Comprehensive Loss [Abstract]
Net loss	$ (71,050)	$ (47,705)	$ (26,390)	$ (59,724)	$ (118,755)	$ (86,114)
Change in cumulative translation adjustment, net of tax	(1,916)	$ 1,073	(7,053)	$ 4,388	(843)	(2,665)
Comprehensive loss	$ (72,966)		$ (33,443)		$ (119,598)	$ (88,779)