Property and Equipment (Depreciation and Depletion Expense) (Details) - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Feb. 08, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Oil and gas properties depletion		$ 130,439
Other property and equipment depreciation		2,375
Total depreciation and depletion expense		$ 132,814
Predecessor
Property, Plant and Equipment [Line Items]
Oil and gas properties depletion	$ 11,021		$ 83,537	$ 49,481
Other property and equipment depreciation	609		5,240	4,004
Total depreciation and depletion expense	$ 11,630		$ 88,777	$ 53,485