Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	90,000,000	90,000,000
Common Stock, shares issued	39,677,291	38,872,663
Treasury Stock at cost, shares	3,201,858	2,970,573