Income Taxes (Deferred Income Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Abstract]
Accrued liabilities	$ 5,287	$ 6,538
Employee benefits and compensation	15,100	15,794
Inventories	6,809	4,758
Stock options and restricted stock	8,596	7,485
Pension and postretirement benefits	60,455	41,930
Derivatives	15,072
Cellulosic biofuel tax credit carryforward	167,452	200,334
Total deferred tax assets	278,771	276,839
Property, plant and equipment	(216,109)	(225,620)
Goodwill and intangible assets	(10,676)	(8,174)
Investment in joint venture	(1,121)	(1,049)
Derivatives		(954)
Total deferred tax liabilities	(227,906)	(235,797)
Net deferred tax assets	$ 50,865	$ 41,042