Consolidated Balance Sheets (Unaudited) (Parenthetical)	Jun. 30, 2011 USD ($)	Dec. 31, 2010 USD ($)
Stockholders' equity:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	143,943,839	143,943,624
Common stock, shares outstanding	139,027,039	139,026,824
Treasury stock, shares	4,916,800	4,916,800