Exploratory Well Costs (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Balance at January 1	$ 25,897
Additions Pending the Determination of Proved Reserves	86,624
Reclassifications to Proved Properties	(34,087)
Costs Charged to Expense (1)	(23,872)	[1]
Balance at September 30	$ 54,562

[1] Includes capitalized exploratory well costs charged to either dry hole costs or impairments.