Condensed Consolidated Statements of Changes in Common Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Foreign Currency Translation Adjustment	Unrealized Holding Gains/(Losses)	Other Change in Stockholders Equity [Member]	Total Stockholders Equity
Balance, at Dec. 31, 2010		$ 150	$ (892,012)	$ 1,963,092	$ (204,926)	$ 21,094	$ (27,857)	$ 239	$ 859,780
Net (loss) income	240,121				240,121				240,121
Net foreign currency translation adjustment, net of tax	(21,434)					(21,434)			(21,434)
Net unrealized gain on investments, net of tax	48,553						48,553		48,553
Repurchases of common stock under incentive plans			(24)	0					(24)
Issuance of common stock under benefit plans				404					405
Amortization of restricted stock				1,603					1,603
Additional convertible debt issuance costs, net				(22)					(22)
Stock-based compensation expense				995					995
Dividends declared				(333)	(334)				(667)
Balance, at Jun. 30, 2011		151	(892,036)	1,965,739	34,861	(340)	20,696	239	1,129,310
Balance, at Dec. 31, 2011	1,182,291	151	(892,052)	1,966,565	96,227	54	11,471	(125)	1,182,291
Net (loss) income	(288,491)				(288,491)				(288,491)
Net foreign currency translation adjustment, net of tax	(8)					(8)			(8)
Net unrealized gain on investments, net of tax	6,926						6,926		6,926
Repurchases of common stock under incentive plans			(32)						(32)
Issuance of common stock under benefit plans		0		213					213
Amortization of restricted stock				1,101					1,101
Stock-based compensation expense				(446)					(446)
Dividends declared				(666)	0				(666)
Balance, at Jun. 30, 2012	$ 900,888	$ 151	$ (892,084)	$ 1,966,767	$ (192,264)	$ 46	$ 18,397	$ (125)	$ 900,888