Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (185,829)	$ (277,192)	$ (102,777)
Cash flow hedges:
Change in unrealized gain (loss) on cash flow hedges, net of tax expense (benefit) of $819, ($1) and ($1,251), respectively	7,587	(19,422)	9,422
Less reclassification for realized net (gain) loss included in net loss, net of tax expense of ($819), $74 and $509, respectively	(7,587)	19,965	(10,650)
Net change, net of tax	0	543	(1,228)
Available-for-sale investments:
Change in unrealized gain (loss) on investments	(68)	125	(126)
Less reclassification for realized net (gain) loss included in net loss	11	(13)	(6)
Net change, net of tax	(57)	112	(132)
Change in foreign currency translation adjustment, net of tax	0	314	(309)
Comprehensive loss	$ (185,886)	$ (276,223)	$ (104,446)