Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - shares	Jun. 30, 2023	Dec. 31, 2022
Common Class A [Member]
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	2,832,966	2,791,449
Treasury shares, issued (in shares)	54,074	47,412
Common Class B [Member]
Common stock, shares authorized (in shares)	2,500,000	2,500,000
Common stock, shares issued (in shares)	914,283	914,283
Treasury shares, issued (in shares)	182,435	182,435