Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS
Cash and cash equivalents	$ 825,901	$ 630,299
Accounts receivable, net	407,372	362,863
Inventories	490,777	450,028
Prepaid expenses and other current assets	12,495	15,482
Deferred income taxes	19,611	17,288
Total current assets	1,756,156	1,475,960
Property, plant and equipment, net	1,232,066	1,170,334
Equity investments	46,741	46,314
Restricted cash	96,283	150,288
Other assets, net	135,575	111,248
Total assets	3,266,821	2,954,144
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	227,034	204,774
Accrued liabilities	137,561	118,804
Total current liabilities	364,595	323,578
Long-term debt	764,563	764,482
Deferred income taxes	330,791	315,518
Other liabilities	50,560	45,496
Total liabilities	1,510,509	1,449,074
Commitments and contingencies (Notes 6 and 18)
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; 66,601,909 and 66,256,144 shares issued at December 31, 2011 and 2010, respectively	666	663
Common stock, held in treasury, at cost; 69,816 shares at December 31, 2011	(2,518)
Additional paid-in capital	467,796	452,703
Retained earnings	1,299,438	1,058,737
Accumulated other comprehensive (loss) income
Benefits liability, net of tax	(15,143)	(12,328)
Cumulative translation adjustment	4,888	5,295
Unrealized holding gains on investments, net of tax	1,185
Total stockholders' equity	1,756,312	1,505,070
Total liabilities and stockholders' equity	$ 3,266,821	$ 2,954,144