Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation expense on property, plant and equipment			$ 48,300	$ 48,900	$ 46,400
Impairment of property, plant and equipment held for use			10,913	9,107	285
Depreciation expense on railcar assets leased to others			$ 20,000	$ 18,600	$ 17,600
Grain
Property, Plant and Equipment [Line Items]
Impairment of property, plant and equipment	$ 10,900
Impairment of property, plant and equipment held for use	5,600
Impairment of property, plant and equipment held for sale	$ 5,300
Retail
Property, Plant and Equipment [Line Items]
Impairment of property, plant and equipment held for use		$ 6,000
Impairment charges related to software		500
Plant Nutrient
Property, Plant and Equipment [Line Items]
Impairment of property, plant and equipment held for use		$ 2,300