CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Discount of notes	$ 70,468
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	4,000,000	4,000,000
Preferred stock, shares issued
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	73,083,000	71,502,000
Common stock, shares outstanding	73,083,000	71,502,000
Senior Convertible Notes Due 2018
Discount of notes	25,354	54,542
Senior Notes Due 2019
Discount of notes	$ 45,114