Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Inventory, Net [Abstract]
Grain	$ 465,453	$ 570,337	$ 298,580
Ethanol and by-products	18,516	5,461	5,381
Agricultural fertilizer and supplies	57,637	118,716	112,892
Lawn and garden fertilizer and corncob products	21,714	37,001	22,585
Retail merchandise	30,685	25,612	27,492
Railcar repair parts	2,777	3,063	2,252
Other	309	269	369
Total inventories	$ 597,091	$ 760,459	$ 469,551