Annual report pursuant to Section 13 and 15(d)

Supplemental Oil and Gas Information (Unaudited) - Discounted Future Net Cash Flows (Details)

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Supplemental Oil and Gas Information (Unaudited) - Discounted Future Net Cash Flows (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Jun. 30, 2012
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]      
Discount Rate 10.00%    
Future cash inflows $ 493,901 $ 666,800  
Future production costs (226,464) (283,279)  
Future development costs (23,594) (33,017)  
Future income tax expense (73,820) (112,193)  
Future net cash flows 170,023 238,311  
10% annual discount (82,980) (130,635)  
Standardized measures of discounted future net cash flows 87,043 107,676 130,075
United States
     
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]      
Future cash inflows 493,901 610,853  
Future production costs (226,464) (244,703)  
Future development costs (23,594) (28,922)  
Future income tax expense (73,820) (112,193)  
Future net cash flows 170,023 225,035  
10% annual discount (82,980) (127,644)  
Standardized measures of discounted future net cash flows 87,043 97,391 121,496
Australia
     
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]      
Future cash inflows 0 55,947  
Future production costs 0 (38,576)  
Future development costs 0 (4,095)  
Future income tax expense 0 0  
Future net cash flows 0 13,276  
10% annual discount 0 (2,991)  
Standardized measures of discounted future net cash flows $ 0 $ 10,285 $ 8,579