Exit Costs and Assets Held for Sale (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment part of disposal group, held for sale	$ 10,028,000	$ 9,816,000	$ 10,028,000	$ 37,859,000
Exit charges	$ 3,500,000	0	$ 11,300,000
Disposal Group, Held-for-sale, Not Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment part of disposal group, held for sale				37,900,000
Disposal Group, Held-for-sale, Not Discontinued Operations | Retail Store
Restructuring Cost and Reserve [Line Items]
Property, plan and equipment held-for-sale		4,200,000		4,200,000
Disposal Group, Held-for-sale, Not Discontinued Operations | Rail Group
Restructuring Cost and Reserve [Line Items]
Property, plan and equipment held-for-sale		4,100,000
Disposal Group, Held-for-sale, Not Discontinued Operations | Grain Group
Restructuring Cost and Reserve [Line Items]
Property, plan and equipment held-for-sale		1,300,000
Disposal Group, Held-for-sale, Not Discontinued Operations | Plant Nutrient Group
Restructuring Cost and Reserve [Line Items]
Property, plan and equipment held-for-sale		$ 200,000		1,600,000
Disposal Group, Held-for-sale, Not Discontinued Operations | TENNESSEE | Grain Group
Restructuring Cost and Reserve [Line Items]
Property, plan and equipment held-for-sale				19,500,000
Inventory, held-for-sale				11,400,000
Commodity derivative, held-for-sale				$ 1,200,000