CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	66,174,767	66,174,767
Common stock, shares outstanding	48,093,949	47,703,684
Treasury stock, shares	18,080,818	18,471,083