Supplemental Information On Oil And Natural Gas Producing Activities (Capitalized Costs) (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Supplemental Information On Oil And Natural Gas Producing Activities [Abstract]
Proved property	[1]	$ 731,548	$ 649,432
Unproved property	[1]	39	1,560
Land		501	501
Total property costs	[1]	732,088	651,493
Materials and supplies	[1]	1,056	1,056
Total	[1]	733,144	652,549
Less: accumulated depreciation, depletion, amortization and impairments	[1]	(652,167)	(517,239)
Oil and natural gas properties and equipment, net	[1]	$ 80,977	$ 135,310

[1] Capitalized costs include the cost of equipment and facilities for our oil and natural gas producing activities. Proved property costs include capitalized costs for leaseholds holding proved reserves; development wells and related equipment and facilities (including uncompleted development well costs); and support equipment. Unproved property costs include capitalized costs for oil and natural gas leaseholds where proved reserves do not exist.