Consolidated Balance Sheet (Current Period Unaudited) (Parentheticals) - $ / shares $ / shares in Thousands	Jun. 30, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	2,123,806	2,130,681
Common stock, shares outstanding (in shares)	2,123,806	2,130,681
Treasury shares, issued (in shares)	37,208	15,795
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	2,500,000	2,500,000
Common stock, shares issued (in shares)	596,848	779,283
Common stock, shares outstanding (in shares)	596,848	779,283
Treasury shares, issued (in shares)	182,435	5,667