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L. SUPPLEMENTARY FINANCIAL INFORMATION ON OIL AND NATURAL GAS EXPLORATION, DEVELOPMENT (Details - Oil and gas operations) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Extractive Industries [Abstract]                      
Oil and gas sales                   $ 791  
Operating expenses                   (707)  
Depreciation, depletion and amortization                   (400)  
Impairment of oil and gas properties $ (2,626) (2,626)
Results of operations                   $ (2,862)