Note 4 - Restructuring Charges - Charges Related to the Wind Down Plan (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Costs accrued	$ 617	$ 585	$ 1,957	$ 988
Integration Program [Member]
Costs accrued			2,100	2,700
Integration Program [Member] | Employee Severance [Member]
Accrued restructuring, beginning balance			5,826	1,236
Costs accrued			1,125	234
Amounts paid or charged			(5,321)	(1,446)
Impact of currency exchange			(64)	(17)
Accrued restructuring, ending balance	1,566	7	1,566	7
Integration Program [Member] | Other Restructuring [Member]
Accrued restructuring, beginning balance			0	0
Costs accrued			832	754
Amounts paid or charged			(832)	(385)
Impact of currency exchange			0	0
Accrued restructuring, ending balance	0	369	0	369
Integration Program [Member] | Employee Severance and Other Exit Costs [Member]
Accrued restructuring, beginning balance			5,826	1,236
Costs accrued			1,957	988
Amounts paid or charged			(6,153)	(1,831)
Impact of currency exchange			(64)	(17)
Accrued restructuring, ending balance	$ 1,566	$ 376	$ 1,566	$ 376