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Properties and Equipment, Net - Schedule of Net Changes in Capitalized Exploratory Well Costs (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Net changes in capitalized exploratory well costs      
Balance at beginning of period $ 0 $ 0 $ 19,511
Additions to capitalized exploratory well costs pending the determination of proved reserves 0 0 0
Reclassifications to wells, facilities, and equipment based on the determination of proved reserves 0 0 0
Capitalized exploratory well costs charged to expense 0 0 (19,511)
Balance at end of period $ 0 $ 0 $ 0