Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2011	Dec. 31, 2010
Condensed Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	213,381,697	213,370,086
Common stock, shares outstanding	177,136,116	175,782,683
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, series A convertible preferred stock: shares issued	1,600,000	1,600,000
Preferred stock, series A convertible preferred stock: shares outstanding	0	0
Common stock in treasury, shares	36,245,581	37,587,403