Annual report pursuant to Section 13 and 15(d)

PLANT, PIPELINE AND EQUIPMENT (Details)

v3.8.0.1
PLANT, PIPELINE AND EQUIPMENT (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Property, Plant and Equipment [Line Items]      
Total plant, pipeline and equipment $ 244,982 $ 194,486  
Less accumulated depreciation (63,240) (54,477)  
PLANT, PIPELINE, AND EQUIPMENT, NET (Note 9) 181,742 140,009  
Interest capitalized for construction 937 450 $ 141
Capitalized labor costs 4,344 2,889 3,803
Amortization relating to the platinum catalyst 25 98 $ 84
Platinum Catalyst [Member]      
Property, Plant and Equipment [Line Items]      
Total plant, pipeline and equipment 1,612 1,612  
Land [Member]      
Property, Plant and Equipment [Line Items]      
Total plant, pipeline and equipment 5,428 5,376  
Plant, Pipeline and Equipment [Member]      
Property, Plant and Equipment [Line Items]      
Total plant, pipeline and equipment 186,946 154,107  
Construction in Progress [Member]      
Property, Plant and Equipment [Line Items]      
Total plant, pipeline and equipment $ 50,996 $ 33,391