Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Segment Reporting Information [Line Items]
Sales and merchandising revenues	$ 1,137,133	$ 1,001,674
Inter-segment sales	4,263	6,280
Interest expense	5,330	7,336
Equity in earnings of affiliates	4,283	7,246
Other income, net	3,246	2,306
Income (loss) before income taxes	27,969	27,194
Grain [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues	699,861	637,967
Inter-segment sales	1	1
Interest expense	3,252	4,840
Equity in earnings of affiliates	5,952	6,230
Other income, net	827	580
Income (loss) before income taxes	19,435	15,101
Ethanol [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues	150,670	132,748
Inter-segment sales
Interest expense	24	412
Equity in earnings of affiliates	(1,671)	1,014
Other income, net	16	58
Income (loss) before income taxes	121	3,571
Plant Nutrient [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues	175,360	123,649
Inter-segment sales	3,083	5,385
Interest expense	710	843
Equity in earnings of affiliates	2	2
Other income, net	118	125
Income (loss) before income taxes	5,828	5,114
Rail [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues	35,859	28,910
Inter-segment sales	203	189
Interest expense	1,178	1,447
Equity in earnings of affiliates
Other income, net	776	753
Income (loss) before income taxes	8,018	3,546
Turf and Specialty [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues	45,127	47,270
Inter-segment sales	976	705
Interest expense	356	449
Equity in earnings of affiliates
Other income, net	201	290
Income (loss) before income taxes	2,202	3,278
Retail [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues	30,256	31,130
Inter-segment sales
Interest expense	196	260
Equity in earnings of affiliates
Other income, net	124	156
Income (loss) before income taxes	(2,749)	(2,664)
Other [Member]
Segment Reporting Information [Line Items]
Sales and merchandising revenues
Inter-segment sales
Interest expense	(386)	(915)
Equity in earnings of affiliates
Other income, net	1,184	344
Income (loss) before income taxes	(4,207)	(874)
Noncontrolling interest
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ (679)	$ 122