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Percentage of issued and outstanding shares acquired.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Weighted average interest rate of debt outstanding.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for a specific purpose other than for financing goods acquired for inventory or imminent delivery to a customer.

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No definition available.

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Description of interest rate for borrowing under credit facility. Includes, but is not limited to, terms and method for determining interest rate.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Period between issuance and maturity of long-term debt, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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The cash outflow to reacquire common stock during the period.

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Debt - Additional Information (Detail) - USD ($)	3 Months Ended
Debt - Additional Information (Detail) - USD ($)	Mar. 29, 2026	Mar. 30, 2025	Dec. 31, 2025	May 27, 2024	Oct. 05, 2022	May 01, 2020
Debt Instrument
Repurchase of common stock	$ 5,518,000	$ 157,475,000
Line of Credit Facility, Maximum Borrowing Capacity					$ 750,000,000	$ 400,000,000
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases	$ 200,000,000
Line of Credit Facility, Interest Rate Description	The interest rate applicable to loans under the Credit Facility are, at Teradyne’s option, equal to either a base rate plus a margin ranging from 0.00% to 0.75% per annum or SOFR plus a margin ranging from 1.10% to 1.85% per annum, based on the consolidated leverage ratio of Teradyne. In addition, Teradyne will pay a commitment fee on the unused portion of the commitments under the Credit Facility ranging from 0.15% to 0.25% per annum, based on the then applicable consolidated leverage ratio.
Term of revolving credit facility						3 years
Available Incremental Amount Under The Credit Facility Not To Exceed Percentage Of Consolidated EBIDTA	15.00%
Percentage of issued and outstanding shares acquired				10.00%
Collateral Pledged [Member]
Debt Instrument
Line of Credit Facility, Interest Rate Description	65
Revolving Credit Facility
Debt Instrument
Debt outstanding	$ 0		$ 200,000,000
interest related to debt	$ 2,900,000
Revolving Credit Facility \| Maximum \| Truist Bank [Member]
Debt Instrument
Commitment fee percentage of unused portion of credit facility	0.25%
Revolving Credit Facility \| Minimum \| Truist Bank [Member]
Debt Instrument
Commitment fee percentage of unused portion of credit facility	0.15%
Revolving Credit Facility \| Base Rate \| Maximum \| Truist Bank [Member]
Debt Instrument
Debt instrument, basis spread on variable rate	0.75%
Revolving Credit Facility \| Base Rate \| Minimum \| Truist Bank [Member]
Debt Instrument
Debt instrument, basis spread on variable rate	0.00%
Revolving Credit Facility \| London Interbank Offered Rate (LIBOR) \| Maximum \| Truist Bank [Member]
Debt Instrument
Debt instrument, basis spread on variable rate	1.85%
Revolving Credit Facility \| London Interbank Offered Rate (LIBOR) \| Minimum \| Truist Bank [Member]
Debt Instrument
Debt instrument, basis spread on variable rate	1.10%
Credit Agreement
Debt Instrument
Weighted-average interest rate on outstanding borrowings			4.86%