Schedule of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2025	Mar. 31, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Revenues	$ 685,680	$ 599,819
Cost of revenues	265,074	255,625
Engineering and development	107,605	93,236
Selling and marketing	87,948	81,989
General and administrative	43,149	41,167
Other segment items	62,880	54,900
Income (loss) before taxes	119,024	72,902
Total assets	3,705,837	3,410,720	$ 3,708,714
Property additions	65,186	44,023
Depreciation and amortization expense	30,302	28,120
Product Test
Segment Reporting Information [Line Items]
Revenues	74,189	77,395
Operating Segments
Segment Reporting Information [Line Items]
Revenues	685,680	599,819
Cost of revenues	265,074	255,625
Engineering and development	107,605	93,236
Selling and marketing	87,948	81,989
General and administrative	41,386	39,395
Other segment items	56,406	46,709
Income (loss) before taxes	127,261	82,865
Total assets	2,345,121	2,321,469
Property additions	65,186	44,023
Depreciation and amortization expense	30,312	28,051
Operating Segments | Semiconductor Test
Segment Reporting Information [Line Items]
Revenues	542,504	434,770
Cost of revenues	202,747	192,894
Engineering and development	80,211	65,649
Selling and marketing	51,697	44,987
General and administrative	26,552	21,062
Other segment items	25,495	26,784
Income (loss) before taxes	155,802	83,394
Total assets	1,396,660	1,407,239
Property additions	59,732	36,554
Depreciation and amortization expense	22,865	19,871
Operating Segments | Robotics
Segment Reporting Information [Line Items]
Revenues	68,987	87,654
Cost of revenues	32,292	34,453
Engineering and development	15,855	15,787
Selling and marketing	24,514	24,821
General and administrative	9,865	13,217
Other segment items	23,638	13,422
Income (loss) before taxes	(37,177)	(14,046)
Total assets	742,621	721,318
Property additions	2,676	5,713
Depreciation and amortization expense	5,941	6,431
Operating Segments | Product Test
Segment Reporting Information [Line Items]
Revenues	74,189	77,395
Cost of revenues	30,035	28,278
Engineering and development	11,539	11,800
Selling and marketing	11,737	12,181
General and administrative	4,969	5,116
Other segment items	7,273	6,503
Income (loss) before taxes	8,636	13,517
Total assets	205,840	192,912
Property additions	2,778	1,756
Depreciation and amortization expense	1,506	1,749
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0
Cost of revenues
Engineering and development
Selling and marketing
General and administrative	1,763	1,772
Other segment items	6,474	8,191
Income (loss) before taxes	(8,237)	(9,963)
Total assets	1,360,716	1,089,251
Property additions
Depreciation and amortization expense	$ (10)	$ 69