Note 4 - Restructuring Charges - Charges Related to the Wind Down Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 25, 2021	Sep. 26, 2020
Costs accrued	$ 31	$ 412		$ 1,988	$ 1,400
Integration Program [Member]
Costs accrued				2,000	1,400
Integration Program [Member] | Employee Severance [Member]
Accrued restructuring, beginning balance				5,826	1,236
Costs accrued				1,124	287
Amounts paid or charged				(6,410)	(1,516)
Impact of currency exchange			$ (83)
Accrued restructuring, ending balance	457	7	457	457	7
Integration Program [Member] | Other Restructuring [Member]
Accrued restructuring, beginning balance				0	0
Costs accrued				864	1,113
Amounts paid or charged				(864)	(1,113)
Impact of currency exchange			0
Accrued restructuring, ending balance	0	0	0	0	0
Integration Program [Member] | Employee Severance and Other Exit Costs [Member]
Accrued restructuring, beginning balance				5,826	1,236
Costs accrued				1,988	1,400
Amounts paid or charged				(7,274)	(2,629)
Impact of currency exchange			(83)
Accrued restructuring, ending balance	$ 457	$ 7	$ 457	$ 457	$ 7