CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 263,425	$ 162,676
Marketable investments	240,032	240,803
Accounts receivable, net of allowance of none for 2012 and 2011	108,949	88,680
Other current assets	37,390	6,188
Prepaid expenses	13,342	9,928
Inventories, net	46,848	45,981
Deferred tax assets	8,199	8,199
Total current assets	718,185	562,455
Marketable investments	248,884	343,899
Marketable investments and cash-restricted	5,348	5,123
Goodwill and other intangibles, net	16,662	22,087
Property, plant and equipment, net	439,894	366,046
Deferred tax assets, net	190,448	190,745
Other assets	28,071	27,724
Total assets	1,647,492	1,518,079
Current liabilities:
Accounts payable	10,130	47,257
Accrued expenses	87,635	57,227
Other current liabilities	129,850	108,093
Total current liabilities	227,615	212,577
Convertible notes	201,970	194,180
Mortgages payable-noncurrent	71,400	71,452
Other liabilities	74,794	80,500
Total liabilities	575,779	558,709
Commitments and contingencies:
Common stock subject to repurchase	10,882	10,882
Stockholders' equity:
Common stock, par value $.01, 245,000,000 shares authorized, 61,892,578 and 61,506,063 shares issued, and 51,162,680 and 53,609,645 shares outstanding at September 30, 2012 and December 31, 2011, respectively	619	615
Additional paid-in capital	1,013,434	992,718
Accumulated other comprehensive loss	(9,524)	(10,885)
Treasury stock at cost, 10,729,898 and 7,896,418 shares at September 30, 2012 and December 31, 2011, respectively	(413,923)	(282,998)
Retained earnings	470,225	249,038
Total stockholders' equity	1,060,831	948,488
Total liabilities and stockholders' equity	1,647,492	1,518,079
Preferred stock
Stockholders' equity:
Preferred stock
Series A junior participating preferred stock
Stockholders' equity:
Preferred stock