Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, authorized shares	50,000,000	50,000,000
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized shares	150,000,000	150,000,000
Common stock, issued shares	78,002,812	77,843,883
Common stock, outstanding shares	78,002,812	77,843,883