Inventories (Details) $ in Thousands, bu in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) bu	Sep. 30, 2020 USD ($) bu	Dec. 31, 2020 USD ($) bu
Inventory [Line Items]
Grain and other agricultural products	$ 732,512	$ 557,808	$ 1,025,809
Frac sand and propane	18,481	10,064	12,477
Ethanol and co-products	105,052	59,543	114,895
Plant nutrients and cob products	161,759	120,173	139,885
Total inventories	1,017,804	747,588	1,293,066
Readily marketable inventory	$ 700,300	$ 523,300	$ 983,200
Bushels of grain held in storage for others and excluded from inventory calculations | bu	2.0	2.3	3.0
Inventory write down	$ 3,399	$ 10,933
COVID-19 Pandemic
Inventory [Line Items]
Inventory write down		$ 10,900