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