Financial Instruments - Schedule of Impact that Derivatives not Qualifying as Hedging Instruments in Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Price risk management activities expense	[1]	$ (109,579)	$ (51,976)

[1] The Company paid $3.0 million and $20.4 million in net cash settlements for the three months ended March 31, 2019 and 2018, respectively.