Note 10 - Per Share Data - Weighted Average Number of Common Shares (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Basic weighted average shares outstanding (in shares)	11,444,697	12,955,198	12,393,058	12,897,303
Dilutive effect of outstanding restricted share units (in shares)	45,411	63,416	34,181	53,628
Weighted average dilutive shares outstanding (in shares)	11,490,108	13,018,614	12,427,739	12,950,931