Property And Equipment (Summary Of Property And Equipment) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Unproved properties	$ 69,739
Proved oil and gas properties	2,163,279
Accumulated depletion and impairment	(1,455,268)
Proved oil and gas properties, net	708,011
Total oil and gas properties, net	777,750	$ 763,337
Land	5,600
Fresh water wells	27,742
Produced water disposal system	104,334
Gas processing plant and gathering lines	396,513
Office furniture, equipment and vehicles	3,772
Accumulated depreciation and impairment	(80,997)
Other property and equipment, net	456,964	444,269
Total property and equipment, net	$ 1,234,714	1,207,606
Predecessor
Property, Plant and Equipment [Line Items]
Unproved properties		74,217
Proved oil and gas properties		2,110,346
Accumulated depletion and impairment		(1,421,226)
Proved oil and gas properties, net		689,120
Total oil and gas properties, net		763,337
Land		5,600
Fresh water wells		27,366
Produced water disposal system		104,498
Gas processing plant and gathering lines		380,470
Office furniture, equipment and vehicles		3,703
Accumulated depreciation and impairment		(77,368)
Other property and equipment, net		444,269
Total property and equipment, net		$ 1,207,606