Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Sales and merchandising revenues	$ 1,315,834	$ 1,338,167	$ 2,452,967	$ 2,339,841
Inter-segment sales	6,039	3,849	10,302	10,129
Interest expense	5,380	7,562	10,710	14,898
Equity in earnings of affiliates	5,096	12,512	9,379	19,758
Other income, net	2,671	2,018	5,917	4,324
Income (loss) before income taxes	45,827	72,010	73,796	99,204
Identifiable assets	1,794,774	1,543,849	1,794,774	1,543,849	1,734,123
Grain
Segment Reporting Information [Line Items]
Sales and merchandising revenues	718,911	797,130	1,418,772	1,435,097
Inter-segment sales	0	1	1	2
Interest expense	2,687	3,859	5,939	8,699
Equity in earnings of affiliates	7,505	5,428	13,457	11,658
Other income, net	489	522	1,316	1,102
Income (loss) before income taxes	15,277	36,541	34,712	51,642
Identifiable assets	844,526	772,995	844,526	772,995	883,395
Ethanol
Segment Reporting Information [Line Items]
Sales and merchandising revenues	167,758	164,704	318,428	297,452
Inter-segment sales	0	0	0	0
Interest expense	185	274	209	686
Equity in earnings of affiliates	(2,410)	7,082	(4,081)	8,096
Other income, net	20	37	36	95
Income (loss) before income taxes	(2,105)	8,830	(1,984)	12,401
Identifiable assets	212,094	93,059	212,094	93,059	148,975
Plant Nutrient
Segment Reporting Information [Line Items]
Sales and merchandising revenues	308,797	259,823	484,157	383,472
Inter-segment sales	5,334	3,221	8,417	8,606
Interest expense	632	973	1,342	1,816
Equity in earnings of affiliates	1	2	3	4
Other income, net	1,010	134	1,128	259
Income (loss) before income taxes	27,953	24,077	33,781	29,191
Identifiable assets	214,617	281,691	214,617	281,691	240,543
Rail
Segment Reporting Information [Line Items]
Sales and merchandising revenues	32,046	29,501	67,905	58,411
Inter-segment sales	208	0	411	189
Interest expense	1,156	1,511	2,334	2,958
Equity in earnings of affiliates	0	0	0	0
Other income, net	824	841	1,600	1,594
Income (loss) before income taxes	7,199	2,763	15,217	6,309
Identifiable assets	310,651	214,971	310,651	214,971	246,188
Turf and Specialty
Segment Reporting Information [Line Items]
Sales and merchandising revenues	43,845	41,551	88,972	88,821
Inter-segment sales	497	627	1,473	1,332
Interest expense	312	372	668	821
Equity in earnings of affiliates	0	0	0	0
Other income, net	289	259	490	549
Income (loss) before income taxes	2,753	1,778	4,955	5,056
Identifiable assets	66,580	61,141	66,580	61,141	69,487
Retail
Segment Reporting Information [Line Items]
Sales and merchandising revenues	44,477	45,458	74,733	76,588
Inter-segment sales	0	0	0	0
Interest expense	157	207	353	467
Equity in earnings of affiliates	0	0	0	0
Other income, net	155	144	279	300
Income (loss) before income taxes	1,428	1,877	(1,321)	(787)
Identifiable assets	56,986	54,243	56,986	54,243	52,018
Other
Segment Reporting Information [Line Items]
Sales and merchandising revenues	0	0	0	0
Inter-segment sales	0	0	0	0
Interest expense	251	366	(135)	(549)
Equity in earnings of affiliates	0	0	0	0
Other income, net	(116)	81	1,068	425
Income (loss) before income taxes	(5,950)	(4,673)	(10,157)	(5,547)
Identifiable assets	89,320	65,749	89,320	65,749	93,517
Noncontrolling Interest
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ (728)	$ 817	$ (1,407)	$ 939