Inventories (Details) $ in Thousands, bu in Millions	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) bu
Inventory, Net [Abstract]
Grain	$ 527,471	$ 505,217
Ethanol and co-products	11,918	11,003
Plant nutrients and cob products	145,693	126,962
Railcar repair parts	5,722	5,521
Total inventories	$ 690,804	$ 648,703
Grain held in storage and excluded from inventory calculations (bushels) | bu		1.0