Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Convertible Senior Notes Due March 2028 [Member]	Dec. 31, 2013 Convertible Senior Notes Due March 2028 [Member]	Sep. 30, 2014 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member]	Sep. 30, 2014 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member]
Earnings Per Share (Textual) [Abstract]
Number of shares of common stock equivalents related to convertible debt							1,387,957	814,235	2,008,749	998,830
Debt Instrument, Interest Rate, Stated Percentage					3.25%	3.25%
Basic EPS
Net income (loss) available to common stockholders	$ 3,466	$ (46,265)	$ (76,846)	$ (69,035)
Weighted average shares
Basic (in shares)	102,470,000	100,778,000	102,427,000	96,893,000
Effect of share based compensation plans (in shares)	91,000	0	0	0
Diluted (in shares)	102,561,000	100,778,000	102,427,000	96,893,000
Income (loss) per share
Basic (in dollars per share)	$ 0.03	$ (0.46)	$ (0.75)	$ (0.71)
Diluted (in dollars per share)	$ 0.03	$ (0.46)	$ (0.75)	$ (0.71)