Supplemental Information On Oil And Gas Exploration And Production Activities (Unaudited) - Summary of Capitalized Costs, Impairment, and Depreciation, Depletion and Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Oil and gas properties, successful efforts method:
Accumulated impairment	$ (121,100)	$ (121,100)
Proved properties, net of accumulated impairments	970,808	755,443
Unproved properties, net of accumulated impairments	260,271	266,140
Land	5,382	5,382
Total oil and gas properties, net of accumulated impairments	1,236,461	1,026,965
Accumulated depreciation, depletion and amortization	(195,567)	(127,256)
Net oil and gas properties	1,040,894	899,709
Proved property
Oil and gas properties, successful efforts method:
Proved properties	1,046,208	830,843
Accumulated impairment	(75,400)	(75,400)
Proved properties, net of accumulated impairments	970,808	755,443
Unproved property
Oil and gas properties, successful efforts method:
Accumulated impairment	(45,690)	(45,688)
Unproved properties	305,961	311,828
Unproved properties, net of accumulated impairments	$ 260,271	$ 266,140