Quarterly report pursuant to Section 13 or 15(d)

Commodity Derivative Positions (Detail)

v3.7.0.1
Commodity Derivative Positions (Detail)
$ in Thousands
3 Months Ended
Mar. 31, 2017
USD ($)
bbl
$ / bbl
Dec. 31, 2016
USD ($)
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Derivative Liability $ 8,361 $ 27,369
Settlement Agreement [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Fair Value Asset 0  
Fair Value Liability $ 142  
Crude Oil | Second Quarter 2017 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 4,408  
Derivative, Swap Type, Average Fixed Price | $ / bbl 48.62  
Fair Value Asset $ 0  
Fair Value Liability $ 1,003  
Crude Oil | Third Quarter 2017 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 4,408  
Derivative, Swap Type, Average Fixed Price | $ / bbl 48.62  
Fair Value Asset $ 0  
Fair Value Liability $ 1,286  
Crude Oil | Fourth Quarter 2017 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 4,408  
Derivative, Swap Type, Average Fixed Price | $ / bbl 48.62  
Fair Value Asset $ 0  
Fair Value Liability $ 1,355  
Crude Oil | First Quarter 2018 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 3,476  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.12  
Fair Value Asset $ 0  
Fair Value Liability $ 881  
Crude Oil | Second Quarter 2018 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 3,476  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.12  
Fair Value Asset $ 0  
Fair Value Liability $ 838  
Crude Oil | Third Quarter 2018 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 3,476  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.12  
Fair Value Asset $ 0  
Fair Value Liability $ 780  
Crude Oil | Fourth Quarter 2018 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 3,476  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.12  
Fair Value Asset $ 0  
Fair Value Liability $ 718  
Crude Oil | First Quarter 2019 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 2,916  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.90  
Fair Value Asset $ 0  
Fair Value Liability $ 359  
Crude Oil | Second Quarter 2019 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 2,916  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.90  
Fair Value Asset $ 0  
Fair Value Liability $ 338  
Crude Oil | Third Quarter 2019 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 2,916  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.90  
Fair Value Asset $ 0  
Fair Value Liability $ 329  
Crude Oil | Fourth Quarter 2019 [Member]    
Derivative Instruments Related to Oil and Gas Production [Line Items]    
Instrument Swaps  
Notional Volume, per day | bbl 2,916  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.90  
Fair Value Asset $ 0  
Fair Value Liability $ 332