Note 6 - Employee Benefit Plans - Stock Option Activity Under Share-based Compensation Plans (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Outstanding, beginning of year (in shares)	363	405	472
Outstanding, weighted average exercise price, beginning of year (in dollars per share)	$ 10.27	$ 10.22	$ 10.20
Exercised (in shares)	(101)	(42)	(67)
Exercised, weighted average exercise price (in dollars per share)	$ 10.95	$ 9.82	$ 10.10
Outstanding, end of year (in shares)	262	363	405
Outstanding, weighted average exercise price, end of year (in dollars per share)	$ 10.01	$ 10.27	$ 10.22
Options exercisable at year end (in shares)	262	363	405
Options exercisable at year end, weighted average exercise price (in dollars per share)	$ 10.01	$ 10.27	$ 10.22