Note 10 - Segment and Geographic Information - Summary of Current Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2022	Jun. 26, 2021	Jun. 25, 2022	Jun. 26, 2021
Net sales	$ 217,226	$ 244,803	$ 414,983	$ 470,291
Profit (loss) for reportable segments		42,079		81,135
Gain (Loss) on Disposition of Business	(0)	75,779	(0)	75,664
Interest expense	(919)	(1,831)	(1,900)	(4,406)
Interest income	308	94	419	144
Gain (Loss) on Extinguishment of Debt, Total	(128)	0	(232)	(1,761)
Income from operations before taxes	$ 37,666	112,755	$ 65,529	143,937
Corporate, Non-Segment [Member]
Corporate expenses		(3,366)		(6,839)
Semiconductor Test and Inspection [Member]
Net sales		231,125		443,531
Profit (loss) for reportable segments		40,601		77,228
PCB Test [Member]
Net sales		13,678		26,760
Profit (loss) for reportable segments		$ 1,478		$ 3,907