Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue
Total revenues from contracts with customers	$ 598,992	$ 769,627	$ 1,812,965	$ 2,941,767
(Loss) gain on derivatives not designated as hedges	(427,182)	180,313	(11,320)	455,952
Net marketing services and other	317	1,636	4,613	7,282
Total operating revenues	172,127	951,576	1,806,258	3,405,001
Natural gas sales
Disaggregation of Revenue
Total revenues from contracts with customers	556,950	726,076	1,698,396	2,763,792
NGLs sales
Disaggregation of Revenue
Total revenues from contracts with customers	38,380	34,880	102,897	151,004
Oil sales
Disaggregation of Revenue
Total revenues from contracts with customers	3,662	8,671	11,672	26,971
Net marketing services and other
Disaggregation of Revenue
Net marketing services and other	$ 317	$ 1,636	$ 4,613	$ 7,282