Property Acquisitions and Divestiture - Additional Information (Details)
6 Months Ended
Mar. 02, 2018
USD ($)
a
Wells
Feb. 08, 2018
USD ($)
a
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Dec. 21, 2017
USD ($)
Business Acquisition [Line Items]            
Purchase price of undeveloped net acres     $ 107,193,000 $ 405,244,000    
Unproved properties acquired     1,838,303,000   $ 1,952,680,000  
Proved properties     2,101,875,000   $ 1,602,002,000  
Proceeds from sale     $ 146,090,000 $ 10,675,000    
Northern Delaware Basin            
Business Acquisition [Line Items]            
Undeveloped net acres acquired | a   4,000        
Purchase price of undeveloped net acres   $ 94,700,000        
Gas and oil area, working interest, percent   92.00%        
Amount placed in escrow           $ 8,600,000
Settlement adjustments   $ 200,000        
Net purchase price of undeveloped net acres   94,500,000        
Unproved properties acquired   80,700,000        
Proved properties   13,800,000        
Capitalized transaction costs   $ 200,000        
Reeves County            
Business Acquisition [Line Items]            
Undeveloped net acres acquired | a 8,600          
Number of wells sold (in wells) | Wells 12          
Proceeds from sale $ 140,700,000          
Average working interest 32.00%          
Gain (loss) on sale $ 0