Schedule of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 29, 2024		Oct. 01, 2023		Sep. 29, 2024		Oct. 01, 2023		Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues		$ 737,298	[1]	$ 703,732	[1]	$ 2,066,996	[2]	$ 2,005,699	[2]
Income (loss) before income taxes	[3],[4]	158,984		144,280		451,289		385,767
Total assets		3,769,728	[5]	3,370,655	[5]	3,769,728	[5]	3,370,655	[5]	$ 3,486,824
System Test
Segment Reporting Information [Line Items]
Revenues		73,312	[1]	83,203	[1]	209,435	[2]	252,106	[2]
Wireless Test
Segment Reporting Information [Line Items]
Revenues		32,601	[1]	36,974	[1]	93,457	[2]	119,472	[2]
Operating Segments
Segment Reporting Information [Line Items]
Revenues		737,298		703,732		2,066,996		2,005,699
Income (loss) before income taxes	[3],[4]	156,373		147,862		394,869		393,442
Total assets	[5]	2,357,481		2,338,069		2,357,481		2,338,069
Operating Segments | Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		542,734		497,863		1,497,552		1,387,580
Income (loss) before income taxes	[3],[4]	163,778		136,451		401,475		361,676
Total assets	[5]	1,308,031		1,382,444		1,308,031		1,382,444
Operating Segments | System Test
Segment Reporting Information [Line Items]
Revenues		73,312		83,203		209,435		252,106
Income (loss) before income taxes	[3],[4]	12,522		23,754		36,138		67,629
Total assets	[5]	178,291		178,904		178,291		178,904
Operating Segments | Robotics
Segment Reporting Information [Line Items]
Revenues		88,651		85,692		266,552		246,541
Income (loss) before income taxes	[3],[4]	(24,206)		(21,812)		(56,099)		(66,704)
Total assets	[5]	794,277		684,207		794,277		684,207
Operating Segments | Wireless Test
Segment Reporting Information [Line Items]
Revenues		32,601		36,974		93,457		119,472
Income (loss) before income taxes	[3],[4]	4,279		9,469		13,355		30,841
Total assets	[5]	76,882		92,514		76,882		92,514
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues		0		0		0		0
Income (loss) before income taxes	[3],[4]	2,611		(3,582)		56,420		(7,675)
Total assets	[5]	$ 1,412,247		$ 1,032,586		$ 1,412,247		$ 1,032,586

[1] Includes $0.8 million and $1.4 million in 2024, and 2023, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.”

[2] Includes $2.5 million and $3.9 million in 2024 and 2023, respectively, for leases of Teradyne’s systems recognized outside Accounting Standards Codification (“ASC”) 606 “Revenue from Contracts with Customers.”

[3] Included in Corporate and Eliminations are interest income, interest expense, net foreign exchange gains (losses), intercompany eliminations, severance charges, pension, acquisition and divestiture related fees, and an expense for the modification of outstanding equity awards.

[4] Included in income (loss) before taxes are charges related to restructuring and other, expense for the modification of outstanding equity awards, legal settlement, pension mark-to-market, and inventory charges.

[5] Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities, and certain other assets.