Consolidated Balance Sheets (Parentheticals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Class A Common Stock [Member]
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	180,000,000	180,000,000
Common Stock, Shares, Issued	65,632,309	64,584,102
Common Stock, Shares, Outstanding	52,938,267	51,934,137
Treasury Stock, Shares	12,694,042	12,649,965
Class B Common Stock [Member]
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Shares, Issued	1,020,485	1,608,989
Common Stock, Shares, Outstanding	1,020,485	1,608,989