Exploratory Well Costs (Details) $ in Thousands	6 Months Ended
	Jun. 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	55,669
Reclassifications to Proved Properties	(2,178)
Costs Charged to Expense (1)	(10,988)	[1]
Balance at June 30	$ 68,400

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