Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 515,121	$ 156,313
Accounts receivable, net of allowance for doubtful accounts and customer deductions of $5,108 and $5,034 as of June 30, 2012 and December 31, 2011, respectively	353,527	319,988
Inventories	258,620	254,675
Prepaid expenses and other current assets	33,929	18,298
Federal and state income taxes receivable	85,769
Deferred income taxes	38,720	62,789
Total current assets	1,285,686	812,063
Property, plant and equipment, net	1,393,730	1,476,654
Goodwill	71,555	58,214
Other intangible assets, net	35,594	25,042
Other long-term assets	44,926	40,526
Total assets	2,831,491	2,412,499
Current liabilities:
Current maturities of long-term debt	414,657	15,000
Capital lease obligations	933	718
Accounts payable	134,113	154,855
Dividends payable	24,480	19,680
Accrued interest	12,782	12,584
Federal and state income taxes payable		10,404
Accrued liabilities	102,983	163,259
Total current liabilities	689,948	376,500
Long-term liabilities:
Long-term debt	786,110	793,448
Capital lease obligations	25,394	21,114
Deferred income taxes	125,056	11,924
Pension and postretirement benefit plans	151,819	148,686
Cellulosic biofuel tax reserve	102,051	102,051
Other long-term liabilities	28,393	29,866
Total long-term liabilities	1,218,823	1,107,089
Stockholders' equity:
Common stock, par value $0.01 per share, 300,000,000 shares authorized, 98,092,959 and 98,324,974 shares issued as of June 30, 2012 and December 31, 2011, respectively	981	983
Additional paid in capital	363,174	351,804
Retained earnings	661,600	673,960
Accumulated other comprehensive loss, net of tax:
Unrealized loss on treasury locks, net	(31,900)	(23,289)
Unrealized loss on foreign currency exchange contracts	(403)	(413)
Unfunded employee benefit obligations	(70,732)	(74,076)
Total accumulated other comprehensive loss	(103,035)	(97,778)
Common stock held in treasury, at cost (2,355 shares as of December 31, 2011)		(59)
Total stockholders' equity	922,720	928,910
Total liabilities and stockholders' equity	$ 2,831,491	$ 2,412,499