Quarterly report pursuant to Section 13 or 15(d)

Oil and Gas Activities (Costs Incurred in Oil and Gas Property Acquisition, Exploration and Development Activities) (Details)

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Oil and Gas Activities (Costs Incurred in Oil and Gas Property Acquisition, Exploration and Development Activities) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 15 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]      
Impairment loss $ 0 $ 890  
Proved 30,301   29,563
Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment, Period Increase (Decrease) (5,955)   (5,814)
Unproved 5,119   5,312
Exploration Costs 7,929   923
Impairment of Oil and Gas Properties 0 890  
United States
     
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]      
Proved 28,039   27,606
Unproved 269   261
Exploration Costs 7,190   235
Australia
     
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]      
Proved 8,217   7,771
Unproved 3,755   3,976
United Kingdom
     
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]      
Unproved 1,095   1,075
Exploration Costs $ 739   $ 688