Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Inventory, Net [Abstract]
Grain	$ 504,484	$ 570,337	$ 248,447
Ethanol and by-products	17,277	5,461	4,799
Agricultural fertilizer and supplies	101,896	118,716	151,099
Lawn and garden fertilizer and corncob products	24,709	37,001	22,794
Retail merchandise	30,767	25,612	28,386
Railcar repair parts	2,852	3,063	2,434
Other	307	269	355
Total inventories	$ 682,292	$ 760,459	$ 458,314