Consolidated Balance Sheets (Parenthetical) (Unaudited) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	24,771,866	24,208,549
Treasury stock, shares	1,817,546	1,642,018