Consolidated Balance Sheets (Parentheticals) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	61,547,863	61,366,859
Common stock, shares outstanding	33,075,092	32,897,642
Treasury Stock, Shares	28,472,771	28,469,217