Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

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Fair Value Measurements (Details) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended
Dec. 31, 2016
Dec. 31, 2016
Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Securities available-for-sale $ 1,542,000 $ 1,542,000 $ 601,000
Rolling gross production average   60 days  
One Stone Exchange Agreement      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Asset impairment charges     11,300,000
Impairment of proved oil and gas properties 7,800,000    
Accounts receivable, impairment charges 100,000    
Exploration costs previously capitalized 3,400,000    
Recurring      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Securities available-for-sale 1,542,000 $ 1,542,000 601,000
Contingent consideration payable 0 0 0
Recurring | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Securities available-for-sale 1,542,000 1,542,000 601,000
Recurring | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Contingent consideration payable $ 0 $ 0 $ 0