Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred tax assets related to:
Expenses not yet deducted for tax purposes	$ 200,698	$ 163,367
Pension liability not yet deducted for tax purposes	377,846	279,204
Capital loss	16,803	24,580
Valuation allowance	(16,803)	(24,784)
Deferred Tax Assets Total	578,544	442,367
Deferred tax liabilities related to:
Employee and retiree benefits	188,206	178,806
Inventory	66,044	72,767
Property, plant, and equipment	47,413	33,474
Other	43,225	17,728
Deferred Tax Liabilities Total	344,888	302,775
Net deferred tax asset	233,656	139,592
Current portion of deferred tax liability	17,250	17,800
Noncurrent net deferred tax asset	$ 250,906	$ 157,392