Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Basic EPS
Net loss available to common stockholders	$ (15,821)	$ 31,060	$ 11,127	$ 82,135
Net Income available to common stockholders, Shares	89,429,000	89,449,000	89,550,000	89,350,000
Net Income available to common stockholders, Per-Share	$ (0.18)	$ 0.35	$ 0.12	$ 0.92
Effect of Dilutive Securities
Equity awards, Income	0	0	0	0
Equity awards, Shares	0	290,000	140,000	352,000
Diluted EPS
Net loss available to common stockholders	$ (15,821)	$ 31,060	$ 11,127	$ 82,135
Net income available to common stockholders, shares	89,429,000	89,739,000	89,690,000	89,702,000
Net Income available to common stockholders, Per-Share	$ (0.18)	$ 0.35	$ 0.12	$ 0.92
Stock Options [Member]
Earnings Per Share (Textual) [Abstract]
Number of shares of common stock equivalents related to convertible debt	772,368	1,129,562	640,660	1,326,763
Convertible Senior Notes Due March 2028 [Member]
Earnings Per Share (Textual) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.25%		3.25%