Oil And Natural Gas Properties (Properties) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Oil And Natural Gas Properties
Proved property	$ 731,617	$ 731,548
Unproved property	42	39
Land	501	501
Total property costs	732,160	732,088
Materials and supplies	1,056	1,056
Total	733,216	733,144
Less: Accumulated depreciation, depletion, amortization and impairments	(666,123)	(652,167)
Oil and natural gas properties and equipment, net	$ 67,093	$ 80,977