Interest Expense on Teradyne's Senior Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2024	Oct. 01, 2023	Sep. 29, 2024	Oct. 01, 2023
Debt Instrument
Contractual interest expense on the coupon	$ 0	$ 74	$ 0	$ 312
Amortization of debt issuance fees recognized as interest expense	0	0	0	113
Total interest expense on the convertible debt	$ 0	$ 74	$ 0	$ 425