Exploratory Well Costs (Details) $ in Thousands	3 Months Ended
	Mar. 31, 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	25,068
Reclassifications to Proved Properties	(2,178)
Costs Charged to Expense	(4,474)	[1]
Balance at March 31	$ 44,313

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