Schedule of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	[1]	$ 704,355	$ 494,099
Income (loss) before taxes		197,069	93,979
Total assets		2,820,388	2,616,643	$ 2,787,014
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		484,489	340,853
Income (loss) before taxes		153,816	83,049
Total assets		921,108	770,967
System Test
Segment Reporting Information [Line Items]
Revenues	[1]	116,076	58,220
Income (loss) before taxes		48,407	15,340
Total assets		137,056	98,916
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		60,305	66,136
Income (loss) before taxes		(15,335)	(5,295)
Total assets		643,011	596,899
Wireless Test
Segment Reporting Information [Line Items]
Revenues	[1]	43,485	29,041
Income (loss) before taxes		10,220	3,628
Total assets		106,400	73,066
Corporate And Others [Member]
Segment Reporting Information [Line Items]
Revenues		0	(151)
Income (loss) before taxes		(39)	(2,743)
Total assets		$ 1,012,813	$ 1,076,795

[1] Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “Revenue from Contracts with Customers.