Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (113,988)	$ (69,274)	$ (187,316)	$ (49,953)
Derivative financial instruments:
Reclassification adjustment for gain included in net loss	(2)	(1)	(3)	(3)
Investments in marketable securities:
Unrealized holding gain	9	31	23	31
Reclassification adjustment for gain included in net loss	(15)		(47)
Total other comprehensive (loss) gain	(8)	30	(27)	28
Comprehensive loss	$ (113,996)	$ (69,244)	$ (187,343)	$ (49,925)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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