Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 895,142	$ 825,901
Accounts receivable, net	444,609	407,372
Inventories	422,405	490,777
Prepaid expenses and other current assets	14,106	12,495
Deferred income taxes	19,614	19,611
Total current assets	1,795,876	1,756,156
Property, plant and equipment, net	1,263,556	1,232,066
Equity investments	46,039	46,741
Restricted cash	65,607	96,283
Other assets, net	158,969	135,575
Total assets	3,330,047	3,266,821
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	197,449	227,034
Accrued liabilities	114,514	137,561
Total current liabilities	311,963	364,595
Long-term debt	764,583	764,563
Deferred income taxes	340,953	330,791
Other liabilities	49,518	50,560
Total liabilities	1,467,017	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; 66,687,994 and 66,601,909 shares issued at March 31, 2012 and December 31, 2011, respectively	667	666
Common stock, held in treasury, at cost; 69,816 shares at March 31, 2012 and December 31, 2011	(2,518)	(2,518)
Additional paid-in capital	474,408	467,796
Retained earnings	1,382,337	1,299,438
Accumulated other comprehensive income
Benefits liability, net of tax	(14,787)	(15,143)
Cumulative translation adjustment	5,400	4,888
Unrealized holding gains on investments, net of tax	17,523	1,185
Total stockholders' equity	1,863,030	1,756,312
Total liabilities and stockholders' equity	$ 3,330,047	$ 3,266,821