Consolidated Balance Sheets (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
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	74,162,972	69,674,185
Common Stock, Shares, Outstanding	61,362,665	56,945,384
Treasury Stock, Shares	12,800,307	12,728,801
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	758,138	793,138
Common Stock, Shares, Outstanding	758,138	793,138