Inventories (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014 bu	Dec. 31, 2013 bu	Mar. 31, 2013 bu
Inventory, Net [Abstract]
Grain	$ 488,492	$ 432,893	$ 507,927
Ethanol and by-products	17,658	14,453	25,531
Agricultural fertilizer and supplies	151,144	100,593	157,882
Lawn and garden fertilizer and corncob products	37,218	39,960	30,343
Retail merchandise	26,205	22,505	28,097
Railcar repair parts	4,661	4,312	3,469
Other	206	207	129
Total inventories	$ 725,584	$ 614,923	$ 753,378
Bushels of grain held in storage and excluded from inventory calculations	5,600,000	13,300,000	17,700,000