Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Stock Options [Member]	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2013 Stock Options [Member]	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2013 Convertible Senior Notes Due March 2028 [Member]	Dec. 31, 2012 Convertible Senior Notes Due March 2028 [Member]
Earnings Per Share (Textual) [Abstract]
Number of shares of common stock equivalents related to convertible debt					1,202,100	632,213	1,202,100	632,213
Debt Instrument, Interest Rate, Stated Percentage									3.25%	3.25%
Basic EPS
Net loss available to common stockholders	$ (35,040)	$ 22,973	$ (22,770)	$ 26,948
Net Income available to common stockholders, Shares	99,833,000	89,631,000	94,918,000	89,611,000
Net Income available to common stockholders, Per-Share	$ (0.35)	$ 0.26	$ (0.24)	$ 0.30
Effect of Dilutive Securities
Equity awards, Income	0	0	0	0
Equity awards, Shares	0	102,000	0	166,000
Diluted EPS
Net loss available to common stockholders	$ (35,040)	$ 22,973	$ (22,770)	$ 26,948
Net income available to common stockholders, shares	99,833,000	89,733,000	94,918,000	89,777,000
Net Income available to common stockholders, Per-Share	$ (0.35)	$ 0.26	$ (0.24)	$ 0.30