Inventories (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Classes of inventories
Grain	$ 589,039	$ 570,337	$ 558,467
Ethanol and by-products	4,416	5,461	4,768
Agricultural fertilizer and supplies	129,186	118,716	153,559
Lawn and garden fertilizer and corncob products	30,017	37,001	27,396
Retail merchandise	31,681	25,612	27,800
Railcar repair parts	2,992	3,063	2,715
Other	315	269	312
Total inventories	$ 787,646	$ 760,459	$ 775,017