5. COMMODITY DERIVATIVE INSTRUMENTS (Details)	Dec. 31, 2017 USD ($) bbl MMBbls		Dec. 31, 2016 USD ($) bbl MMBbls
Swaps
Volume | MMBbls	0		406,655
Price(NYMEX)	$ 0		$ 2.66	[1]
Volume | bbl	0		11,533
Price(LLS)	$ 0		$ 40.25
3-Way Collars
Volume | MMBbls	248,023		0
Ceiling sold price (call) (NYMEX)	$ 3.28	[1]	$ 0
Floor purchased price (put) (NYMEX)	2.95	[1]	0
Floor sold price (short put) (NYMEX)	$ 2.38		$ 0
Volume | bbl	113,029		23,449
Ceiling sold price (call) (WTI)	$ 77		$ 47.15
Floor purchased price (put) (WTI)	60		40
Floor sold price (short put) (WTI)	$ 45		$ 30
Put Spread
Volume | bbl	0		98,902
Floor purchased price (put) (WTI)	$ 0		$ 62.27
Floor sold price (short put) (WTI)	$ 0		$ 40

[1] Price is a weighted average