Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
LIABILITIES AND STOCKHOLDERS' EQUITY
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	93,902,191	93,143,102
Treasury stock, shares	2,818,350	2,766,912