Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Segment Reporting Information [Line Items]
Sales and merchandising revenues	$ 1,003,294		$ 1,271,970
Inter-segment sales	8,282		9,132
Interest expense	6,002		6,404
Equity in earnings of affiliates, net	20,501		7,804
Other income (expense), net	19,612		2,726
Income (loss) before income taxes	39,901		21,391
Identifiable assets	2,125,583		2,151,788		2,273,556
Grain
Segment Reporting Information [Line Items]
Sales and merchandising revenues	583,159		836,495
Inter-segment sales	0		332
Interest expense	2,775		3,849
Equity in earnings of affiliates, net	1,884		7,910
Other income (expense), net	18,346	[1]	571	[1]
Income (loss) before income taxes	11,306		8,299
Identifiable assets	979,608		1,025,350		921,914
Ethanol
Segment Reporting Information [Line Items]
Sales and merchandising revenues	188,820		199,309
Interest expense	100		326
Equity in earnings of affiliates, net	18,617		(106)
Other income (expense), net	(226)		231
Income (loss) before income taxes	19,824		2,479
Identifiable assets	224,931		209,666		229,797
Plant Nutrient
Segment Reporting Information [Line Items]
Sales and merchandising revenues	107,630		111,902
Inter-segment sales	7,367		7,697
Interest expense	771		918
Other income (expense), net	185		(25)
Income (loss) before income taxes	(1,411)		(562)
Identifiable assets	311,219		323,653		268,238
Rail
Segment Reporting Information [Line Items]
Sales and merchandising revenues	52,302		46,364
Inter-segment sales	109		104
Interest expense	1,656		1,513
Other income (expense), net	710		946
Income (loss) before income taxes	15,045		14,574
Identifiable assets	303,532		302,717		312,654
Turf and Specialty
Segment Reporting Information [Line Items]
Sales and merchandising revenues	43,725		47,187
Inter-segment sales	806		999
Interest expense	418		402
Other income (expense), net	307		275
Income (loss) before income taxes	1,375		4,001
Identifiable assets	110,538		97,842		89,939
Retail
Segment Reporting Information [Line Items]
Sales and merchandising revenues	27,658		30,713
Interest expense	170		215
Other income (expense), net	112		114
Income (loss) before income taxes	(2,335)		(3,169)
Identifiable assets	47,710		53,668		44,910
Other
Segment Reporting Information [Line Items]
Interest expense	112		(819)
Other income (expense), net	178		614
Income (loss) before income taxes	(7,224)		(3,965)
Identifiable assets	148,045		138,892		406,104
Noncontrolling Interests
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ 3,321		$ (266)

[1] Increase is related to gain on LTG partial share redemption. See Note 8. Related Party Transactions for details of the LTG gain in 2014.