Restructuring Activities (Narrative) (Details) $ in Millions	Dec. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	$ 4.2
Severance Costs - Selling, General And Administration [Member]
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	3.8
Severance Costs - Costs Of Goods Sold [Member]
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	0.4
Corporate Activities [Member]
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	3.1
Agribusiness and Energy Services [Member]
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	0.7
Ethanol Production [Member]
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	0.4
Accrued and Other Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Severance cost recognized	$ 2.7