Per Share Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Numerator
Net income (loss) - basic and diluted	$ 11,651	$ (43,447)
Denominator
Weighted-average shares - basic (in shares)	93,446	89,162
Effect of dilutive securities (in shares):
Stock options (in shares)	13,630
Restricted stock (in shares)	658
Dilutive potential shares (in shares)	14,288
Weighted-average shares - diluted (in shares)	107,734	89,162
Net income (loss) per share - basic (in dollars per share)	$ 0.12	$ (0.49)
Net income (loss) per share - diluted (in dollars per share)	$ 0.11	$ (0.49)
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)	89	22,378
Weighted average exercise price (in dollars per share)	$ 94.13	$ 20.26
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)		845
Convertible Senior Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)	4,761
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number, in thousands (in shares)	4,761