Consolidated Balance Sheets (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Class A Common Stock [Member]
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Voting Rights	1	1
Common Stock, Shares Authorized	180,000,000	180,000,000
Common Stock, Shares, Issued	69,674,185	65,632,309
Common Stock, Shares, Outstanding	56,945,384	52,938,267
Treasury Stock, Shares	12,728,801	12,694,042
Class B Common Stock [Member]
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Voting Rights	10	10
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Shares, Issued	793,138	1,020,485
Common Stock, Shares, Outstanding	793,138	1,020,485