Equity Method Investments - Operating Results (Details) - Illinois Corn Processings LLC $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items]
Net sales	$ 78,062
Cost of sales and expenses	(79,224)
Net loss	(1,162)
Depreciation and amortization	$ 1,720