Annual report pursuant to Section 13 and 15(d)

Commodity Derivative Positions (Detail)

v3.6.0.2
Commodity Derivative Positions (Detail)
$ in Thousands
12 Months Ended
Dec. 31, 2016
USD ($)
bbl
counterparty
$ / bbl
$ / bbl
Crude Oil  
Derivative Instruments Related to Oil and Gas Production [Line Items]  
Derivative, Swap Type, Average Fixed Price | $ / bbl 49.12
Settlement Agreement [Member]  
Derivative Instruments Related to Oil and Gas Production [Line Items]  
Fair Value Liability $ 818
Fourth Quarter 2019 [Member] | Crude Oil  
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 $ 1,414
Third Quarter 2019 [Member] | Crude Oil  
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 $ 1,423
Second Quarter 2019 [Member] | Crude Oil  
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 $ 1,438
First Quarter 2019 [Member] | Crude Oil  
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 $ 1,471
Fourth Quarter 2018 [Member] | Crude Oil  
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 $ 2,091
Third Quarter 2018 [Member] | Crude Oil  
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 $ 2,140
Second Quarter 2018 [Member] | Crude Oil  
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 $ 2,193
First Quarter 2018 [Member] | Crude Oil  
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 $ 2,267
Fourth Quarter 2017 [Member] | Crude Oil  
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 $ 3,260
Third Quarter 2017 [Member] | Crude Oil  
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 $ 3,290
Second Quarter 2017 [Member] | Crude Oil  
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 $ 3,110
First Quarter 2017 [Member] | Crude Oil  
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 $ 2,454
Commodity contracts  
Derivative Instruments Related to Oil and Gas Production [Line Items]  
Number Of Derivative Counterparty | counterparty 3