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. 28, 2019	Dec. 29, 2018
Accumulated benefit obligation at beginning of year	$ 2,880	$ 3,148
Interest cost	115	105
Actuarial gain	(258)	(216)
Benefits paid	(166)	(157)
Accumulated benefit obligation at end of year	2,571	2,880
Plan assets at end of year
Funded status	$ (2,571)	$ (2,880)