Note 6 - Employee Benefit Plans - Post-retirement Benefit Obligation to Funded Status and Liability (Details) - Postretirement Health Coverage [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2021	Dec. 26, 2020
Accumulated benefit obligation at beginning of year	$ (2,398)	$ (2,571)
Interest cost	(49)	(75)
Actuarial gain	241	134
Benefits paid	109	114
Accumulated benefit obligation at end of year	(2,097)	(2,398)
Plan assets at end of year	0	0
Funded status	$ (2,097)	$ (2,398)