Derivatives (Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	$ 5,448	$ 13,325
Liability Derivatives Fair Value	1,088	730
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	3,064	4,235
Liability Derivatives Fair Value	4	0
Designated as Hedging Instrument [Member] | Corn Option [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	2,876	4,235
Designated as Hedging Instrument [Member] | Corn Option [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	106	0
Designated as Hedging Instrument [Member] | Natural Gas Swap [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	82	0
Designated as Hedging Instrument [Member] | Natural Gas Swap [Member] | Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	4	0
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	2,384	9,090
Liability Derivatives Fair Value	1,084	730
Not Designated as Hedging Instrument [Member] | Corn Option [Member] | Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	21	122
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	1,153	8,939
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	1,063	608
Not Designated as Hedging Instrument [Member] | Corn options and futures [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	1,167	151
Not Designated as Hedging Instrument [Member] | Soybean Meal [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	$ 64	$ 0