Goodwill and Intangible Assets (Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Amortized intangible assets
Original Cost	$ 39,493	$ 40,859
Accumulated Amortization	20,010	14,798
Net Book Value	19,483	26,061
Rail | Acquired customer list
Amortized intangible assets
Original Cost	3,862	3,462
Accumulated Amortization	3,421	3,362
Net Book Value	441	100
Rail | Acquired non-compete agreement
Amortized intangible assets
Original Cost	250
Accumulated Amortization	17
Net Book Value	233
Rail | Lease intangible
Amortized intangible assets
Original Cost	2,816	2,410
Accumulated Amortization	2,150	1,778
Net Book Value	666	632
Plant Nutrient | Acquired customer list
Amortized intangible assets
Original Cost	9,596	9,596
Accumulated Amortization	3,054	2,071
Net Book Value	6,542	7,525
Plant Nutrient | Acquired non-compete agreement
Amortized intangible assets
Original Cost	2,119	2,119
Accumulated Amortization	1,501	1,219
Net Book Value	618	900
Plant Nutrient | Acquired marketing agreement
Amortized intangible assets
Original Cost	1,607	1,607
Accumulated Amortization	1,228	1,029
Net Book Value	379	578
Plant Nutrient | Acquired supply agreement
Amortized intangible assets
Original Cost	4,846	4,846
Accumulated Amortization	2,477	1,959
Net Book Value	2,369	2,887
Plant Nutrient | Trademarks and technology
Amortized intangible assets
Original Cost	3,300	3,300
Accumulated Amortization	1,035	495
Net Book Value	2,265	2,805
Grain | Acquired customer list
Amortized intangible assets
Original Cost	5,850	8,450
Accumulated Amortization	2,286	717
Net Book Value	3,564	7,733
Grain | Acquired non-compete agreement
Amortized intangible assets
Original Cost	175	175
Accumulated Amortization	116	81
Net Book Value	59	94
Grain | Acquired supply agreement
Amortized intangible assets
Original Cost	340	340
Accumulated Amortization	0	0
Net Book Value	340	340
Grain | Acquired grower agreement
Amortized intangible assets
Original Cost	300	300
Accumulated Amortization	300	275
Net Book Value	0	25
Turf & Specialty | Acquired customer list
Amortized intangible assets
Original Cost	750	600
Accumulated Amortization	72	10
Net Book Value	678	590
Turf & Specialty | Acquired non-compete agreement
Amortized intangible assets
Original Cost	155	100
Accumulated Amortization	17	2
Net Book Value	138	98
Ethanol | Acquired non-compete agreement
Amortized intangible assets
Original Cost	250	250
Accumulated Amortization	209	84
Net Book Value	41	166
Ethanol | Lease intangible
Amortized intangible assets
Original Cost	2,123	2,123
Accumulated Amortization	1,716	1,230
Net Book Value	407	893
Various | Patents and other
Amortized intangible assets
Original Cost	1,154	1,181
Accumulated Amortization	411	486
Net Book Value	$ 743	$ 695