Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounts receivable, allowance for doubtful accounts	$ 1,388	$ 1,552
Preferred stock, no 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
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0.1	$ 0.1
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares outstanding (in shares)	2,141,589	2,141,589
Common stock, treasury shares (in shares)	3,323	3,323
Common Class A [Member] | Restricted Stock [Member]
Common stock, treasury shares (in shares)	1,072,769	1,072,769
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.1	$ 0.1
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares outstanding (in shares)	10,620,260	10,642,760
Common stock, treasury shares (in shares)	17,342	17,342
Common Class B [Member] | Restricted Stock [Member]
Common stock, treasury shares (in shares)	3,218,307	3,218,307