8. DERIVATIVES (Tables)

12 Months Ended

Dec. 31, 2016

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives not designated as hedging instruments

	As of December 31, 2016
	Assets			Liabilities
Type of Instrument	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
Commodity contracts	Derivative assets	$	978	Derivative liabilities	$	4,115
		$	978		$	4,115

	As of December 31, 2015
	Assets			Liabilities
Type of Instrument	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
Commodity contracts	Derivative assets	$	2,081	Derivative liabilities	$	1,848
		$	2,081		$	1,848

Recognized gains (losses) on Derivatives

		Realized Gains (Losses)
		For the Years Ended December 31,
Type of Instrument	Statements of Operations Location	2016		2015			2014
Commodity contracts	Cost of goods sold	$	1,386	$	(338	)	$	(1,144	)
		$	1,386	$	(338	)	$	(1,144	)

			Unrealized Gains (Losses)
		For the Years Ended December 31,
Type of Instrument	Statements of Operations Location	2016			2015			2014
Commodity contracts	Cost of goods sold	$	(3,370	)	$	(204	)	$	336
		$	(3,370	)	$	(204	)	$	336