Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Allowance for doubtful accounts	$ 736	$ 685
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized (in shares)	20,000,000	20,000,000
Common stock, outstanding (in shares)	6,308,025	6,206,525
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized (in shares)	10,000,000	10,000,000
Common stock, outstanding (in shares)	679,680	689,577