Property Acquisitions and Divestitures - Silberback Acquisition, Schedule of Assets Acquired and Liabilities Assumed (Details) - Undeveloped Acreage and Oil and Gas Producing Properties From Silverback Exploration, LLC
$ in Thousands
12 Months Ended
Dec. 31, 2018
USD ($)
Business Acquisition [Line Items]  
Total purchase price consideration $ 867,772
Fair value of assets acquired:  
Unproved properties 753,763
Proved properties 116,700
Other property and equipment 56
Total amount attributable to assets acquired 870,519
Fair value of liabilities assumed:  
Liabilities (2,747)
Total fair value of net assets acquired $ 867,772