Consolidated Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 20, 2021	Dec. 26, 2020	Mar. 21, 2020
Receivables, allowance	$ 954	$ 896	$ 565
Preferred stock, shares authorized (in dollars per share)	$ 1,000,000	$ 1,000,000	$ 1,000,000
Preferred stock, par value (in shares)	0	0	0
Preferred stock, shares issued (in shares)	0	0	0
Common stock, shares authorized (in shares)	30,000,000	30,000,000	30,000,000
Common stock, par value (in dollars per share)	$ 0	$ 0	$ 0
Common stock, shares issued (in shares)	13,924,754	13,919,380	14,096,874
Common stock, shares outstanding (in shares)	13,924,754	13,919,380	14,096,874