PROGOLD LIMITED LIABILITY COMPANY (Details) (ProGold Limited Liability Company, USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
ProGold Limited Liability Company
ProGold Limited Liability Company
Interest ownership (as a percent)	49.00%
Financial information for ProGold LLC
Current Assets	$ 144	$ 109	$ 111
Long-Term Assets	80,182	89,670	83,669
Total Assets	80,326	89,779	83,780
Current Liabilities	401	406	405
Long-Term Liabilities	1,500	1,900	1,600
Total Liabilities	1,901	2,306	2,005
Members' Equity	78,425	87,473	81,775
Total Liabilities and Members' Equity	80,326	89,779	83,780
Rent Revenue on Operating Lease	5,653	6,220	25,223
Expenses	3,037	3,098	11,762
Net Income	$ 2,616	$ 3,122	$ 13,461