Schedule of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Revenues	$ 651,797	$ 729,879	$ 1,337,477	$ 1,329,698
Cost of revenues	274,446	296,962	539,520	552,586
Engineering and development	108,869	98,037	216,474	191,272
Selling and marketing	88,494	87,714	176,442	169,703
General and administrative	42,626	39,183	85,774	80,350
Other segment items	40,803	(11,420)	103,683	43,482
Income (loss) before taxes	96,559	219,403	215,584	292,305
Total assets	3,761,862	3,631,706	3,761,862	3,631,706	$ 3,708,714
Property additions	50,408	44,846	115,594	88,869
Depreciation and amortization expense	31,389	30,204	61,691	58,324
Product Test
Segment Reporting Information [Line Items]
Revenues	85,053	79,716	159,242	157,113
Operating Segments
Segment Reporting Information [Line Items]
Revenues	651,797	729,879	1,337,477	1,329,698
Cost of revenues	274,446	296,962	539,520	552,586
Engineering and development	108,869	98,037	216,474	191,272
Selling and marketing	88,494	87,714	176,442	169,703
General and administrative	41,707	39,201	83,093	78,596
Other segment items	45,499	52,403	101,905	99,044
Income (loss) before taxes	92,782	155,562	220,043	238,497
Total assets	2,454,097	2,296,483	2,454,097	2,296,483
Property additions	50,408	44,846	115,594	88,869
Depreciation and amortization expense	31,389	30,236	61,701	58,287
Operating Segments | Semiconductor Test
Segment Reporting Information [Line Items]
Revenues	491,878	559,916	1,034,382	994,686
Cost of revenues	207,201	230,904	409,948	423,797
Engineering and development	82,126	70,961	162,337	136,609
Selling and marketing	52,590	47,113	104,287	92,100
General and administrative	26,132	21,524	52,684	42,586
Other segment items	28,066	32,207	53,561	58,992
Income (loss) before taxes	95,763	157,207	251,565	240,602
Total assets	1,349,429	1,353,880	1,349,429	1,353,880
Property additions	43,593	35,685	103,325	72,239
Depreciation and amortization expense	23,395	21,394	46,260	41,264
Operating Segments | Robotics
Segment Reporting Information [Line Items]
Revenues	74,866	90,247	143,853	177,901
Cost of revenues	34,155	37,409	66,447	71,862
Engineering and development	14,069	16,187	29,924	31,974
Selling and marketing	24,241	28,580	48,755	53,401
General and administrative	9,879	12,429	19,744	25,646
Other segment items	11,055	13,558	34,693	26,910
Income (loss) before taxes	(18,533)	(17,916)	(55,710)	(31,892)
Total assets	745,839	731,264	745,839	731,264
Property additions	3,528	7,607	6,204	13,319
Depreciation and amortization expense	6,068	7,127	12,009	13,558
Operating Segments | Product Test
Segment Reporting Information [Line Items]
Revenues	85,053	79,716	159,242	157,111
Cost of revenues	33,090	28,649	63,125	56,927
Engineering and development	12,674	10,889	24,213	22,689
Selling and marketing	11,663	12,021	23,400	24,202
General and administrative	5,696	5,248	10,665	10,364
Other segment items	6,378	6,638	13,651	13,142
Income (loss) before taxes	15,552	16,271	24,188	29,787
Total assets	358,829	211,339	358,829	211,339
Property additions	3,287	1,554	6,065	3,311
Depreciation and amortization expense	1,926	1,715	3,432	3,465
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Cost of revenues	0	0	0	0
Engineering and development	0	0	0	0
Selling and marketing	0	0	0	0
General and administrative	919	(18)	2,681	1,754
Other segment items	(4,696)	(63,823)	1,778	(55,562)
Income (loss) before taxes	3,777	63,841	(4,459)	53,808
Total assets	1,307,765	1,335,223	1,307,765	1,335,223
Property additions	0	0	0	0
Depreciation and amortization expense	$ 0	$ (32)	$ (10)	$ 37