Note 10 - Segment and Geographic Information - Summary of Current Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2022	Sep. 25, 2021	Sep. 24, 2022	Sep. 25, 2021
Net sales	$ 206,687	$ 225,063	$ 621,670	$ 695,354
Profit (loss) for reportable segments		36,345		117,480
Gain (Loss) on Disposition of Business	(0)	90	(0)	75,754
Interest expense	(1,028)	(966)	(2,928)	(5,372)
Interest income	1,132	53	1,551	197
Gain (Loss) on Extinguishment of Debt, Total	(80)	(1,650)	(312)	(3,411)
Income from operations before taxes	$ 35,075	31,125	$ 100,604	175,062
Corporate, Non-Segment [Member]
Corporate expenses		(2,747)		(9,586)
Semiconductor Test and Inspection [Member]
Net sales		225,063		668,594
Profit (loss) for reportable segments		36,345		113,573
PCB Test [Member]
Net sales		0		26,760
Profit (loss) for reportable segments		$ 0		$ 3,907