Derivative Instruments (Tables)
 3 Months Ended
Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Derivative Instruments
The following table summarizes the approximate volumes and average contract prices of swap contracts the Company had in place as of March 31, 2018:
 
Period
 
Volume (Bbl)
 
Weighted Average Differential ($/Bbl) (1)
Crude oil basis swaps
April 2018 - June 2018
 
455,000

 
$
0.18

 
April 2018 - December 2018
 
1,375,000

 
$
0.00


 
(1) 
The oil basis swap contracts are settled based on the difference between the arithmetic average of ARGUS MIDLAND WTI and ARGUS WTI CUSHING settlements during the relevant calculation period.
 
Period
 
Volume (MMBtu)
 
Weighted Average Differential ($/MMBtu) (1)
Natural gas basis swaps
April 2018 - December 2018
 
1,375,000

 
$
(0.43
)
 
January 2019 - December 2019
 
1,825,000

 
$
(0.43
)
 
(1) 
The natural gas basis swap contracts are settled based on the difference between Inside FERC’s West Texas WAHA price of natural gas and the NYMEX price of Natural Gas during the relevant calculation period.
Schedule of Gains and Losses from Derivative Instruments
The following table presents gains and losses for derivative instruments not designated as hedges for accounting purposes for the periods presented:
 
For the Three Months Ended March 31,
(in thousands)
2018
 
2017
Realized gain (loss) on derivative instruments
$
361

 
$
(397
)
Unrealized gain (loss) on derivative instruments
7,482

 
4,156

Net gain (loss) on derivative instruments
$
7,843

 
$
3,759
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value
The table below summarizes the fair value amounts and the classification in the Consolidated Balance Sheets of the Company’s derivative contracts outstanding at the respective balance sheet dates. Refer to Note 8—Fair Value Measurements for details of the gross and net derivative assets, liabilities and offset amounts as presented in the Consolidated Balance Sheets.
 
 
 
Gross Asset/Liability Amounts
(in thousands)
Balance Sheet Classification
 
March 31, 2018
 
December 31, 2017
Derivative Assets
 
 
 
 
 
Derivative instruments
Current assets
 
$
7,148

 
$
720

Derivative instruments
Noncurrent assets
 
1,188

 
662

Total derivative assets
 
 
$
8,336

 
$
1,382

Derivative Liabilities
 
 
 
 
 
Derivative instruments
Current liabilities
 
$
—

 
$
527