PROGOLD LIMITED LIABILITY COMPANY (Details) - Progold Limited Liability Company [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ProGold Limited Liability Company
Ownership percentage in joint venture	49.00%
Financial information for ProGold LLC
Current Assets	$ 125	$ 133	$ 2,375
Long-Term Assets	42,086	53,386	65,019
Total Assets	42,211	53,519	67,394
Current Liabilities	407	404	2,627
Long-Term Liabilities		400	800
Total Liabilities	407	804	3,427
Members' Equity	41,804	52,715	63,967
Total Liabilities and Members' Equity	42,211	53,519	67,394
Rent Revenue on Operating Lease	22,837	23,106	24,125
Expenses	11,866	12,392	11,919
Net Income	$ 10,971	$ 10,714	$ 12,206