CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
NET LOSS	$ (630,210)	$ (171,799)	$ (133,969)
OTHER COMPREHENSIVE INCOME (LOSS):
Net foreign currency gain (loss)	(2)	(59)	(75)
Unrealized holding gain (loss) arising during the period, net of tax impact of $4,412, $1,581 and $(2,931) for the years ended December 31, 2016, 2015 and 2014, respectively.	(7,692)	(2,878)	5,088
Less reclassifications to net loss, net of tax impact of $42, $(681) and $0 for the years ended December 31, 2016, 2015 and 2014, respectively.	(73)	1,192	0
Net change in unrealized holding gains, net of tax	(7,619)	(4,070)	5,088
Unrealized holding gain arising during the period, net of tax impact of $0, $0 and $(1,214) for the years ended December 31, 2016, 2015 and 2014, respectively.	9,677	17,300	18,078
Less reclassifications to net loss, net of tax impact of $0, $0 and $(365) for the years ended December 31, 2016, 2015 and 2014, respectively.	10,273	19,604	643
Net change in unrealized holding gains (loss), net of tax	(596)	(2,304)	17,435
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	(8,217)	(6,433)	22,448
COMPREHENSIVE LOSS	$ (638,427)	$ (178,232)	$ (111,521)