Reconciliation of Level 3 Fair Value Measurements (Details) - Derivative Financial Instrument Net Assets - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Roll-forward of Level 3 Assets
Fair Value, net assets (liabilities), beginning of period	$ (117,985)	$ 26,958	$ (8,427)	$ 8,414
Fair Value, net assets (liabilities), end of period	(158,653)	(9,215)	(158,653)	(9,215)
Commodity Price Risk Management (loss), net
Roll-forward of Level 3 Assets
Changes in fair value included in statement of operations line item:	(87,036)	(21,521)	(214,556)	32,840
Settlements included in statement of operations line items:	46,368	(14,652)	64,330	(50,469)
Net change in fair value of unsettled derivatives included in statement of operations line item	$ (78,786)	$ (13,171)	$ (210,430)	$ 9,466