Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax liabilities:
Property, plant and equipment and railcar assets leased to others	$ (85,556)	$ (72,997)
Prepaid employee benefits	(16,490)	(15,419)
Investments	(23,180)	(23,262)
Other	(6,402)	(3,205)
Total deferred tax liabilities	(131,628)	(114,883)
Deferred tax assets:
Employee benefits	45,400	42,482
Accounts and notes receivable	1,920	1,909
Inventory	4,800	6,326
Deferred expenses	11,540	16,022
Net operating loss carryforwards	654	1,299
Other	5,038	3,688
Total deferred tax assets	69,352	71,726
Valuation allowance
Net deferred tax assets	69,352	71,726
Net deferred tax liabilities	$ (62,276)	$ (43,157)