Computation of Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024
Net Income Loss Per Common Share
Net Income (Loss)		$ 78,372	$ 186,273	$ 177,269	$ 250,470
Weighted average common shares-basic		159,967	157,804	160,734	155,426
Convertible note hedge warrant shares	[1]	0	4,930	0	6,896
Incremental Common Shares Attributable to Dilutive Effect of Equity Unit Purchase Agreements		6	1	26	2
Dilutive potential common shares		168	5,666	331	7,483
Weighted average common shares-diluted		160,135	163,470	161,065	162,909
Net income per common share-basic		$ 0.49	$ 1.18	$ 1.1	$ 1.61
Net income per common share-diluted		$ 0.49	$ 1.14	$ 1.1	$ 1.54
Restricted Stock Units
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		160	726	302	573
Employee Stock Option [Member]
Net Income Loss Per Common Share
Incremental shares attributable to share based payment arrangements		2	9	3	12

[1] Convertible notes hedge warrant shares were calculated using the difference between the average Teradyne stock price for the period and the warrant price, multiplied by the number of warrant shares. The result of this calculation, representing the total intrinsic value of the warrant, was divided by the average Teradyne stock price for the period.