Business Acquisition (Details Textual) shares in Thousands, $ in Thousands, gal in Millions, bu in Millions		12 Months Ended
	Oct. 07, 2014 USD ($) location transaction T shares bu gal	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	May. 18, 2015 USD ($)	Dec. 31, 2012 USD ($)
Business Acquisition [Line Items]
Cash payments to acquire businesses		$ 128,549	$ 20,037	$ 15,252
Goodwill		63,934	72,365	58,554		$ 54,387
Grain
Business Acquisition [Line Items]
Goodwill		0	46,422	38,165		38,165
Plant Nutrient
Business Acquisition [Line Items]
Goodwill		$ 59,767	21,776	$ 16,222		$ 16,222
Kay Flow Industries, Inc.
Business Acquisition [Line Items]
Percentage of shares outstanding acquired					100.00%
Contingent consideration, minimum					$ 0
Contingent consideration, maximum					24,000
Fair value of consideration for acquisition					129,429
Contingent consideration					400
Working capital adjustment					4,000
Goodwill					47,735
Inventory					$ 25,094
Business acquisitions, 2014
Business Acquisition [Line Items]
Year to date spending on acquisition of business			20,000
Consideration transferred			$ 7,200
Auburn Bean and Grain
Business Acquisition [Line Items]
Percentage of shares outstanding acquired	100.00%
Fair value of consideration for acquisition	$ 60,895
Consideration transferred	$ 60,900
Number of transactions | transaction	2
Cash payments to acquire businesses	$ 5,000
Number of shares in stock for stock merger transaction | shares	637
Shares issued in stock for stock merger transaction, value	$ 35,500
Number of share in stock for stock merger transaction, adjustment to working capital | shares	80
Shares issued in stock for stock merger transaction, adjustment to working capital, value	$ 4,500
Cash paid to acquire additional facilities	$ 20,400
Additional grain storage capacity acquired (bushels) | bu	18.1
Dry grain storage acquired (tons) | T	16,000
Grain storage acquired, liquid nutrient capacity (gallons) | gal	3.7
Goodwill	$ 11,236
Inventory	5,798
Expected tax deductible goodwill	3,900
Auburn Bean and Grain | Grain
Business Acquisition [Line Items]
Goodwill	5,700
Auburn Bean and Grain | Plant Nutrient
Business Acquisition [Line Items]
Goodwill	$ 5,500
Grain operations | Auburn Bean and Grain
Business Acquisition [Line Items]
Number of locations acquired | location	6
Agronomy operations | Auburn Bean and Grain
Business Acquisition [Line Items]
Number of locations acquired | location	4