Annual report pursuant to Section 13 and 15(d)

Supplemental Oil and Gas Information (Unaudited) - Changes in Standardized Measure of Discounted Future Net Cash Flows (Details)

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Supplemental Oil and Gas Information (Unaudited) - Changes in Standardized Measure of Discounted Future Net Cash Flows (Details)
$ in Thousands
 12 Months Ended
Jun. 30, 2016
USD ($)
MBbls
Jun. 30, 2015
USD ($)
Jun. 30, 2014
MBbls
Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves [Roll Forward]      
Adjustment due to suspension of the Company's workover program | MBbls (643)    
Oil (in Mbbls)      
Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves [Roll Forward]      
Adjustment due to suspension of the Company's workover program | MBbls     (643)
United States      
Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves [Roll Forward]      
Fiscal year beginning balance $ 17,017 $ 87,043  
Net change in prices and production costs (10,953) (71,406)  
Revisions of previous quantity estimates (5,757) (54,415)  
Divestiture of reserves 0 0  
Changes in estimated future development costs 4,014 9,071  
Sales and transfers of oil and gas produced (3,208) (440)  
Previously estimated development cost incurred during the period 338 7,749  
Accretion of discount 1,511 8,853  
Net change in income taxes (1) 0 32,188  
Net change in timing and other (375) (1,626)  
Fiscal year ending balance $ 2,587 $ 17,017