Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS (Details)

v3.7.0.1
DERIVATIVE INSTRUMENTS (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
DERIVATIVE INSTRUMENTS [Abstract]      
Feedstock and natural gas usage to operating expenses 67.30% 64.00%  
Derivative [Line Items]      
Unrealized gain (loss) $ 3 $ (6)  
Realized loss $ 21 $ 37  
Maximum [Member]      
Derivative [Line Items]      
Monthly feedstock requirements hedged 40.00%    
Interest Rate Swaps [Member]      
Derivative [Line Items]      
Term loan in pay fixed, receive variable interest rate swap $ 10,000    
Term loan secured by plant, pipeline and equipment 14,000    
Notional amount $ 1,500   $ 1,750
Derivative, variable interest rate 5.83%    
Fair value of interest rate swap - liability $ 34   $ 58