CHANGE IN ACCOUNTING STANDARDS - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue
Corn Revenue	$ 13,379	$ 11,374	$ 27,719	$ 28,741
Method A
Revenue
Total	3,800	2,900	9,200	9,100
Method B
Revenue
Total	$ 9,600	$ 8,500	$ 18,500	$ 19,600