CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets
Cash and cash equivalents	$ 1,110,538	$ 825,901
Accounts receivable, net	418,000	407,372
Inventories	407,124	490,777
Prepaid expenses and other current assets	15,415	12,495
Deferred income taxes	19,693	19,611
Total current assets	1,970,770	1,756,156
Property, plant and equipment, net	1,309,752	1,232,066
Equity investments	44,815	46,741
Restricted cash	20,452	96,283
Other assets, net	96,149	135,575
Total assets	3,441,938	3,266,821
Current liabilities
Accounts payable	208,309	227,034
Accrued liabilities	129,768	137,561
Total current liabilities	338,077	364,595
Long-term debt	764,604	764,563
Deferred income taxes	337,162	330,791
Other liabilities	49,784	50,560
Total liabilities	1,489,627	1,510,509
Commitments and contingencies (Notes 6 and 13)
Stockholders' equity
Preferred stock, $0.01 par value, 50,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.01 par value, 150,000,000 shares authorized; 66,890,711 and 66,601,909 shares issued at June 30, 2012 and December 31, 2011, respectively	669	666
Common stock, held in treasury, at cost; 284,493 and 69,816 shares at June 30, 2012 and December 31, 2011, respectively	(13,302)	(2,518)
Additional paid-in capital	481,895	467,796
Retained earnings	1,492,914	1,299,438
Accumulated other comprehensive loss	(9,865)	(9,070)
Total stockholders' equity	1,952,311	1,756,312
Total liabilities and stockholders' equity	$ 3,441,938	$ 3,266,821