Condensed Consolidated Balance Sheets (Current period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accounts receivable, allowance for doubtful accounts	$ 215	$ 163
Accumulated depreciation	$ 37,394	$ 44,013
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	25,000,000	25,000,000
Common stock, shares issued (in shares)	12,221,484	12,221,484
Common stock, shares outstanding (in shares)	7,201,071	7,702,614
Treasury stock, shares (in shares)	5,020,413	4,818,870