Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting Information [Line Items]
Sales and merchandising revenues	$ 1,680,641		$ 1,138,402	$ 1,315,834	$ 1,137,133	$ 1,297,830		$ 938,660	$ 1,338,167	$ 1,001,674	$ 5,272,010		$ 4,576,331		$ 3,393,791
Inter-segment sales											19,516		19,184		15,793
Interest expense (income)											22,155		25,256		19,865
Equity in earnings of affiliates, net											16,487		41,450		26,007
Other income, net											14,725		7,922		11,652
Income (loss) before income taxes											120,133		147,878		104,143
Identifiable assets	2,182,304					1,734,123					2,182,304		1,734,123		1,699,390
Capital expenditures											69,017		44,162		30,897
Cash invested in affiliates											0		121		395
Acquisition of businesses, net of cash acquired											220,257		2,365		39,293
Depreciation and amortization											48,977		40,837		38,913
Grain
Segment Reporting Information [Line Items]
Sales and merchandising revenues											3,293,632		2,849,358		1,936,813
Inter-segment sales											409		2		3
Interest expense (income)											12,174		13,277		6,686
Equity in earnings of affiliates, net											29,080		23,748		15,648
Other income, net											2,548		2,462		2,557
Income (loss) before income taxes											63,597		87,288		64,374
Identifiable assets	1,104,937	[1]				883,395	[1]				1,104,937	[1]	883,395	[1]	978,273	[1]
Capital expenditures											30,178		24,284		10,343
Acquisition of businesses, net of cash acquired											116,888		0		39,293
Depreciation and amortization											9,554		9,625		7,580
Ethanol
Segment Reporting Information [Line Items]
Sales and merchandising revenues											742,929		641,546		468,639
Inter-segment sales											0		0		0
Interest expense (income)											759		1,048		1,629
Equity in earnings of affiliates, net											(12,598)		17,715		10,351
Other income, net											53		159		176
Income (loss) before income taxes											(3,720)		23,344		17,013
Identifiable assets	206,975	[1]				148,975	[1]				206,975	[1]	148,975	[1]	121,207	[1]
Capital expenditures											1,966		0		0
Cash invested in affiliates											0		0		395
Acquisition of businesses, net of cash acquired											77,400		0		0
Depreciation and amortization											5,003	[2]	382	[2]	371	[2]
Plant Nutrient
Segment Reporting Information [Line Items]
Sales and merchandising revenues											797,033		690,631		619,330
Inter-segment sales											16,135		16,527		13,517
Interest expense (income)											2,832		3,517		3,901
Equity in earnings of affiliates, net											5		(13)		8
Other income, net											1,917		704		1,298
Income (loss) before income taxes											39,254		38,267		30,062
Identifiable assets	230,029	[1]				240,543	[1]				230,029	[1]	240,543	[1]	208,548	[1]
Capital expenditures											18,038		13,296		7,631
Cash invested in affiliates											0		21		0
Acquisition of businesses, net of cash acquired											15,286		2,365		0
Depreciation and amortization											12,014		9,913		10,225
Rail
Segment Reporting Information [Line Items]
Sales and merchandising revenues											156,426		107,459		94,816
Inter-segment sales											622		593		637
Interest expense (income)											4,807		5,677		4,928
Equity in earnings of affiliates, net											0		0		0
Other income, net											7,136		2,866		4,502
Income (loss) before income taxes											42,841		9,778		107
Identifiable assets	289,467					246,188					289,467		246,188		196,149
Capital expenditures											3,896		1,478		927
Depreciation and amortization											15,929		14,780		15,107
Turf & Specialty
Segment Reporting Information [Line Items]
Sales and merchandising revenues											131,026		129,716		123,549
Inter-segment sales											2,350		2,062		1,636
Interest expense (income)											1,233		1,381		1,604
Equity in earnings of affiliates, net											0		0		0
Other income, net											784		880		1,335
Income (loss) before income taxes											2,216		2,000		3,443
Identifiable assets	82,683	[1]				69,487	[1]				82,683	[1]	69,487	[1]	62,643	[1]
Capital expenditures											5,043		2,089		2,237
Acquisition of businesses, net of cash acquired											10,683		0		0
Depreciation and amortization											2,117		1,801		2,032
Retail
Segment Reporting Information [Line Items]
Sales and merchandising revenues											150,964		157,621		150,644
Inter-segment sales											0		0		0
Interest expense (income)											776		899		1,039
Equity in earnings of affiliates, net											0		0		0
Other income, net											554		638		608
Income (loss) before income taxes											(3,951)		(1,520)		(2,534)
Identifiable assets	51,772					52,018					51,772		52,018		52,430
Capital expenditures											2,794		1,230		8,827
Depreciation and amortization											3,002		2,770		2,400
Other
Segment Reporting Information [Line Items]
Sales and merchandising revenues											0		0		0
Inter-segment sales											0		0		0
Interest expense (income)											(426)		(543)		78
Equity in earnings of affiliates, net											0		0		0
Other income, net											1,733		213		1,176
Income (loss) before income taxes											(16,189)		(12,998)		(8,541)
Identifiable assets	216,441	[3]				93,517	[3]				216,441	[3]	93,517	[3]	80,140	[3]
Capital expenditures											7,102		1,785		932
Cash invested in affiliates											0		100		0
Depreciation and amortization											1,358		1,566		1,198
Noncontrolling interests
Segment Reporting Information [Line Items]
Income (loss) before income taxes											$ (3,915)		$ 1,719		$ 219

[1] See Note 12. Business Acquisitions

[2] Increase driven by acquisition of TADE in May 2012

[3] Change driven by increase in cash and cash equivalents and capitalized software