Annual report pursuant to Section 13 and 15(d)

Supplemental Information on Oil and Natural Gas Properties (unaudited) (Narrative) (Details)

v3.8.0.1
Supplemental Information on Oil and Natural Gas Properties (unaudited) (Narrative) (Details)
MBoe in Thousands, $ in Thousands
 2 Months Ended 12 Months Ended
Feb. 23, 2018
item
Dec. 31, 2017
USD ($)
item
MBoe
$ / Boe
Dec. 31, 2016
USD ($)
item
MBoe
$ / Boe
Dec. 31, 2015
USD ($)
item
MBoe
$ / Boe
Dec. 31, 2014
MBoe
Reserve Quantities [Line Items]          
Depletion expense per physical unit of production | $ / Boe   13.82 12.81 19.74  
Lease operating expense per physical unit of production | $ / Boe   5.96 6.88 7.71  
Proved developed and undeveloped reserve, net (energy) | MBoe   136,974 91,580 54,271 32,824
Proved developed and proved undeveloped reserves, percentage change between periods   50.00% 69.00% 65.00%  
Period to convert the PUDs into proved developed reserves   5 years      
Proved undeveloped reserves, percentage change between periods   40.00% 88.00% 75.00%  
Proved undeveloped reserves | MBoe   67,656 48,348 25,654 14,623
Proved undeveloped reserves reclassification to proved developed production | MBoe   (8,281) 6,823    
Proved undeveloped reserves conversion to proved developed reserves, percentage transferred   (17.00%) 27.00%    
Disposed of by Sale          
Reserve Quantities [Line Items]          
Proved developed and undeveloped reserve period increase (decrease) | MBoe     11,168    
Permian Basin [Member]          
Reserve Quantities [Line Items]          
Proved developed and undeveloped reserve period increase (decrease) | MBoe   57,881 48,477    
Number of wells drilled during the period | item   49 29 36  
Number of wells drilled during the period, net | item   38.2 20.9 27.1  
Removal of proved undeveloped locations | item   13      
Proved undeveloped reserves reclassification to proved developed production | MBoe       2,742  
Proved undeveloped reserves conversion to proved developed reserves, percentage transferred       19.00%  
Proved undeveloped reserves conversion to proved developed reserves total cost | $   $ 57,019 $ 43,415 $ 55,933  
Permian Basin [Member] | Continued Horizontal Development [Member]          
Reserve Quantities [Line Items]          
Proved developed and undeveloped reserve period increase (decrease) | MBoe   30,198 12,035 13,774  
Permian Basin [Member] | Acquisitions Net of Divestitures [Member]          
Reserve Quantities [Line Items]          
Proved developed and undeveloped reserve period increase (decrease) | MBoe   3,267 17,482    
Permian Basin [Member] | Removal of Locations [Member]          
Reserve Quantities [Line Items]          
Proved developed and undeveloped reserve period increase (decrease) | MBoe   (5,876)      
Subsequent Event          
Reserve Quantities [Line Items]          
Number of horizontal wells drilled gross | item 8        
Number of horizontal wells drilled net | item 6.0        
Number of completed horizontal wells gross | item 5        
Number of completed horizontal wells net | item 3.0        
Number of horizontal wells in progress gross | item 3        
Number of horizontal wells in progress net | item 3.0