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Supplemental Information on Oil and Natural Gas Producing Activities (Unaudited) - Capitalized Costs Related to Oil and Natural Gas Producing Activities (Details) - USD ($)
$ in Thousands
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Oil and natural gas properties      
Proved $ 1,484,359 $ 1,269,091 $ 1,056,806
Unproved 24,603 60,152 100,884
Total oil and natural gas properties 1,508,962 1,329,243 1,157,690
Less: accumulated depreciation, depletion and impairment (1,129,622) (580,132) (460,431)
Net oil and natural gas properties capitalized costs $ 379,340 $ 749,111 $ 697,259