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Description Of Business And Significant Accounting Policies (Narrative) (Details) - USD ($)
6 Months Ended
Jan. 26, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Description Of Business And Significant Accounting Policies [Line Items]        
Unevaluated properties   $ 0   $ 23,000
Impairment   0 $ 0  
Sale of methane facility assets $ 2,650,000      
Accounts receivable - current   559,000   533,000
Allowance for doubtful accounts   0    
Tax [Member]        
Description Of Business And Significant Accounting Policies [Line Items]        
Accounts receivable - current   129,000   129,000
Accounts receivable - noncurrent   $ 130,000   $ 130,000