Supplemental Oil And Natural Gas Disclosures (Costs Incurred In Oil And Natural Gas Acquisition, Exploration And Development Activities) (Details) - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Feb. 08, 2018	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Costs Incurred in Oil and Natural Gas Acquisition, Exploration and Development Activities
Property acquisition costs, unproved properties		$ 54,587
Property acquisition costs, proved properties		16,300
Costs incurred, exploration		32,130
Costs incurred, development		664,138
Costs Incurred, Total		767,155
Costs Incurred, Additional Information [Abstract]
Additions to asset retirement obligations		5,600
Unproven leasehold acquisition cost		$ 22,300
Predecessor
Costs Incurred in Oil and Natural Gas Acquisition, Exploration and Development Activities
Property acquisition costs, unproved properties	$ 4,240			$ 88,378	$ 66,788
Property acquisition costs, proved properties	327			11,704	68,478
Costs incurred, exploration	3,678			26,836	28,480
Costs incurred, development	37,672			351,570	165,796
Costs Incurred, Total	$ 45,917			478,488	329,542
Costs Incurred, Additional Information [Abstract]
Additions to asset retirement obligations			$ 0	4,400	1,900
Unproven leasehold acquisition cost				$ 45,600
Predecessor | Stone
Costs Incurred, Additional Information [Abstract]
Total cost of business acquisition					$ 65,700