Inventories (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Classes of inventories
Grain	$ 570,337	$ 493,911
Ethanol	5,461	3,356
Agricultural fertilizer and supplies	118,716	90,182
Lawn and garden fertilizer and corncob products	37,001	32,954
Retail merchandise	25,612	24,416
Railcar repair parts	3,063	2,058
Other	269	312
Total inventories	$ 760,459	$ 647,189