Stockholder's Equity (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended	1 Months Ended	6 Months Ended		0 Months Ended		12 Months Ended
	Mar. 31, 2010	Jun. 30, 2011	Dec. 31, 2010	Feb. 28, 2011 4.75% Convertible Senior Notes Due On 2018 [Member]	Jun. 30, 2011 4.75% Convertible Senior Notes Due On 2018 [Member]	Jun. 30, 2011 Additional Paid-In Capital [Member]	Apr. 08, 2009 Common Stock [Member]	Apr. 08, 2009 Warrants [Member]	Dec. 31, 2010 Warrants [Member]
Principal amount		$ 1,000		$ 230,000,000	$ 230,000,000
Convertible senior notes, maturity date		Feb. 01, 2018		Feb. 01, 2018	Feb. 01, 2018
Conversion feature of convertible notes		34,427,000		34,400,000		34,427,000
Deferred tax liability set-up related to the convertible notes (net of finance costs)		23,924,000
Issuance costs				1,900,000			2,000,000
Registered direct offering common stock, raised		309,000				309,000	31,000,000
Registered direct offering common stock yield for cash							29,000,000
Common stock, shares issued		71,349,000	70,259,000				5,927,343		2,227,963
Warrants Issued During Period								5,038,237
Initial exercise price of warrants								$ 10.46
Income recorded within other income	8,300,000
Fair value of warrant liabilities								12,600,000
Proceeds from warrant exercises									8,500,000
Warrant exercised to purchase common stock, shares			5,038,237						812,617
Warrants to purchase common stock on cashless settlement process									4,225,620
Common stock were exercised resulting in forfeiture									1,997,657
Warrants to purchase common stock shares outstanding			0
Warrants and Rights Outstanding			$ 0