From time to time, the Company uses derivative financial instruments to mitigate its exposure to commodity price risk associated with oil, natural gas and NGL prices. The Company records derivative financial instruments on its consolidated balance sheets as either assets or liabilities measured at fair value. The Company has elected not to apply hedge accounting for its existing derivative financial instruments. As a result, the Company recognizes the change in derivative fair value between reporting periods currently in its consolidated statements of operations as an unrealized gain or loss. The fair value of the Company’s derivative financial instruments is determined using industry-standard models that consider various inputs including: (i) quoted forward prices for commodities, (ii) time value of money and (iii) current market and contractual prices for the underlying instruments, as well as other relevant economic measures. The Company has evaluated and considered the credit standings of its counterparties in determining the fair value of its derivative financial instruments.

At December 31, 2018, the Company had various costless collar and swap contracts open and in place to mitigate its exposure to oil and natural gas price volatility, each with a specific term (calculation period), notional quantity (volume hedged) and price floor and ceiling and fixed price for the swaps. Each contract is set to expire at varying times during 2019 and 2020.

The following is a summary of the Company’s open costless collar contracts for oil and natural gas at December 31, 2018.



		Notional Quantity (Bbl or MMBtu)	Weighted Average Price Floor ($/Bbl or $/MMBtu)		Weighted Average Price Ceiling ($/Bbl or $/MMBtu)		Fair Value of Asset (Liability) (thousands)

Commodity	Calculation Period
Oil	01/01/2019 - 12/31/2019	3,720,000	$	53.55	$	72.22	$	31,531
Natural Gas	01/01/2019 - 12/31/2019	2,400,000	$	2.50	$	3.80	164
Total open costless collar contracts							$	31,695

The following is a summary of the Company’s open three-way costless collar contracts for oil at December 31, 2018. Open three-way costless collars consist of a long put (the floor), a short call (the ceiling) and a long call that limits losses on the upside.



Commodity	Calculation Period		Notional Quantity (Bbl)	Weighted Average Price Floor ($/Bbl)		Weighted Average Price, Short Call ($/Bbl)		Weighted Average Price, Long Call ($/Bbl)			Fair Value of Asset (Liability) (thousands)
Oil	01/01/2019 - 12/31/2019		1,320,000	$	60.00	$	75.00	$	78.85		$	18,114
Natural Gas	01/01/2019 - 12/31/2019	2.50	4,800,000	$	2.50	$	3.00	3.24		120	120
Total open three-way costless collar contracts											$	18,234

The following is a summary of the Company’s open basis swaps contracts for oil at December 31, 2018.



Commodity	Calculation Period	Notional Quantity (Bbl or Gal)	Fixed Price ($/Bbl or $/Gal)			Fair Value of Asset (Liability) (thousands)
Oil Basis Swaps	01/01/2020 - 12/31/2020	1,200,000	$	(0.15	)	$	(83	)
Total open swap contracts						$	(83	)

At December 31, 2018, the Company had an aggregate asset value for open derivative financial instruments of $49.8 million.

The Company’s derivative financial instruments are subject to master netting arrangements, and the Company’s counterparties allow for cross-commodity master netting provided the settlement dates for the commodities are the same. The Company does not present different types of commodities with the same counterparty on a net basis in its consolidated balance sheets.

The following table presents the gross asset and liability fair values of the Company’s commodity price derivative financial instruments and the location of these balances in the consolidated balance sheets as of December 31, 2018 and December 31, 2017 (in thousands).



Derivative Instruments	Gross amounts recognized			Gross amounts netted in the consolidated balance sheets			Net amounts presented in the consolidated balance sheets
December 31, 2018
Current assets	$	53,136		$	(3,207	)	$	49,929
Long-term liabilities	(83		)	—			(83		)
Total	$	53,053		$	(3,207	)	$	49,846
December 31, 2017
Current assets	$	131,092		$	(129,902	)	$	1,190
Current liabilities	(146,331		)	129,902			(16,429		)
Total	$	(15,239	)	$	—		$	(15,239	)

The following table summarizes the location and aggregate fair value of all derivative financial instruments recorded in the consolidated statements of operations for the periods presented (in thousands). These derivative financial instruments are not designated as hedging instruments.



		Year Ended December 31,
Type of Instrument	Location in Statement of Operations	2018			2017			2016
Derivative Instrument
Oil	Revenues: Realized gain (loss) on derivatives	$	3,741		$	(3,657	)	$	5,851
Natural Gas	Revenues: Realized (loss) gain on derivatives	(1,407		)	(608		)	3,435
NGLs	Revenues: Realized loss on derivatives	—			(56		)	—
Realized gain (loss) on derivatives		2,334			(4,321		)	9,286
Oil	Revenues: Unrealized gain (loss) on derivatives	65,991			2,638			(18,969		)
Natural Gas	Revenues: Unrealized (loss) gain on derivatives	(906		)	7,077			(22,269		)
Unrealized gain (loss) on derivatives		65,085			9,715			(41,238		)
Total		$	67,419		$	5,394		$	(31,952	)