Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Common Class A [Member]
Common stock, shares authorized (in shares)	60,000,000	60,000,000
Common stock, shares outstanding (in shares)	29,780,999	30,303,818
Treasury stock, shares (in shares)	934,171
Common Class B [Member]
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares outstanding (in shares)	9,621,714	10,093,305
Treasury stock, shares (in shares)	3,274,224	2,616,657
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01