Condensed Consolidated Balance Sheets (Current period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Accounts receivable, allowance for doubtful accounts	$ 170	$ 266
Accumulated depreciation	$ 51,791	$ 52,512
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
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)	12,121,484	12,121,484
Common stock, shares outstanding (in shares)	7,032,528	6,976,144
Treasury stock, shares (in shares)	5,088,956	5,145,340
Series A Preferred Stock [Member]
Preferred stock, shares issued (in shares)	9,926	9,926
Preferred stock, shares outstanding (in shares)	9,926	9,926