Summary of Significant Accounting Policies - Non-cash Impairment Charges (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Non-cash Impairment Charges [Line Items]
Abandonment expense	$ 810		$ 995	$ 1,372	$ 1,317
Impairment and abandonment expense	810		995	1,266,236	1,317
Unproved Oil and Gas Properties
Schedule of Non-cash Impairment Charges [Line Items]
Impairment of Oil and Gas Properties	0	$ 76,300	0	76,298	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

The adjustment to expense previously capitalized costs of drilling exploratory wells when proved reserves are not found or when the entity obtains information that raises substantial doubt about the economic or operational viability of the project.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration