Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	86,588,933	86,572,098
Common stock, shares outstanding	86,588,933	86,572,098
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000