Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Revenues from external customers	$ 1,297,830	$ 938,660	$ 1,338,167	$ 1,001,674	$ 1,153,969	$ 706,825	$ 810,999	$ 721,998	$ 4,576,331	$ 3,393,791	$ 3,025,304
Inter-segment sales									19,184	15,793	14,392
Equity in earnings of affiliates									41,450	26,007	17,463
Other income, net									7,922	11,652	8,331
Interest expense (income)									(25,256)	(19,865)	(20,688)
Income (loss) before taxes									147,878	104,143	61,496
Identifiable assets	1,734,123				1,699,390				1,734,123	1,699,390	1,284,391
Capital expenditures									44,162	30,897	16,560
Cash invested in affiliates									121	395	1,200
Acquisition of businesses									2,365	39,293	30,480
Depreciation and amortization									40,837	38,913	36,020
Grain [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									2,849,358	1,936,813	1,734,574
Inter-segment sales									2	3	9
Equity in earnings of affiliates									23,748	15,648	5,816
Other income, net									2,462	2,557	2,030
Interest expense (income)									13,277	6,686	8,735
Income (loss) before taxes									87,288	64,374	33,777
Identifiable assets	883,395				978,273				883,395	978,273	451,056
Capital expenditures									24,284	10,343	6,129
Acquisition of businesses										39,293
Depreciation and amortization									9,625	7,580	5,161
Ethanol [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									641,546	468,639	419,404
Inter-segment sales
Equity in earnings of affiliates									17,715	10,351	11,636
Other income, net									159	176	289
Interest expense (income)									1,048	1,629	628
Income (loss) before taxes									23,344	17,013	17,577
Identifiable assets	148,975				121,207				148,975	121,207	145,985
Capital expenditures											16
Cash invested in affiliates										395	1,100
Depreciation and amortization									382	371	371
Plant Nutrient [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									690,631	619,330	491,293
Inter-segment sales									16,527	13,517	12,245
Equity in earnings of affiliates									(13)	8	8
Other income, net									704	1,298	1,755
Interest expense (income)									3,517	3,901	3,933
Income (loss) before taxes									38,267	30,062	11,294
Identifiable assets	240,543				208,548				240,543	208,548	205,968
Capital expenditures									13,296	7,631	6,610
Cash invested in affiliates									21
Acquisition of businesses									2,365		30,480
Depreciation and amortization									9,913	10,225	8,665
Rail [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									107,459	94,816	92,789
Inter-segment sales									593	637	634
Equity in earnings of affiliates
Other income, net									2,866	4,502	485
Interest expense (income)									5,677	4,928	4,468
Income (loss) before taxes									9,778	107	(1,034)
Identifiable assets	246,188				196,149				246,188	196,149	194,748
Capital expenditures									1,478	927	297
Depreciation and amortization									14,780	15,107	15,967
Turf and Specialty [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									129,716	123,549	125,306
Inter-segment sales									2,062	1,636	1,504
Equity in earnings of affiliates
Other income, net									880	1,335	1,131
Interest expense (income)									1,381	1,604	1,429
Income (loss) before taxes									2,000	3,443	4,735
Identifiable assets	69,487				62,643				69,487	62,643	63,353
Capital expenditures									2,089	2,237	1,305
Depreciation and amortization									1,801	2,032	2,314
Retail [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									157,621	150,644	161,938
Inter-segment sales
Equity in earnings of affiliates
Other income, net									638	608	683
Interest expense (income)									899	1,039	961
Income (loss) before taxes									(1,520)	(2,534)	(2,843)
Identifiable assets	52,018				52,430				52,018	52,430	45,696
Capital expenditures									1,230	8,827	1,157
Depreciation and amortization									2,770	2,400	2,286
Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers
Inter-segment sales
Equity in earnings of affiliates											3
Other income, net									213	1,176	1,958
Interest expense (income)									(543)	78	534
Income (loss) before taxes									(12,998)	(8,541)	(3,225)
Identifiable assets	93,517				80,140				93,517	80,140	177,585
Capital expenditures									1,785	932	1,046
Cash invested in affiliates									100		100
Depreciation and amortization									1,566	1,198	1,256
Noncontrolling Interest [Member]
Segment Reporting Information [Line Items]
Income (loss) before taxes									$ 1,719	$ 219	$ 1,215