Summary of Significant Accounting Policies - Non-cash Impairment Charges (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Non-cash Impairment Charges [Line Items]
Abandonment expense	$ 276		$ 1,170	$ 1,648	$ 2,487
Impairment and abandonment expense	2,813	$ 1,300,000	1,170	1,269,049	2,487
Unproved Oil and Gas Properties
Schedule of Non-cash Impairment Charges [Line Items]
Impairment of Oil and Gas Properties	2,537	76,300	0	78,835	0
Proved Oil and Gas Properties
Schedule of Non-cash Impairment Charges [Line Items]
Impairment of Oil and Gas Properties	$ 0	$ 1,200,000	$ 0	$ 1,188,566	$ 0