Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Discount of convertible notes	$ 52,889	$ 54,542
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	4,000,000	4,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	72,402,000	71,502,000
Common stock, shares outstanding	72,402,000	71,502,000