Income Taxes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Jul. 03, 2022	Jul. 04, 2021	Dec. 31, 2021
Income Taxes [Line Items]
Tax savings due to the tax holiday	$ 8.3	$ 15.9
Tax savings due to the tax holiday, per share	$ 0.05	$ 0.08
Accrued interest and penalties	$ 0.3		$ 0.3
Interest and penalties related to income tax, expense (benefit)	0.1	$ 0.2
Uncertain tax positions	14.6		$ 14.5
Net decrease in reserves for uncertain tax positions	$ 0.1

Income Taxes [Line Items]

No definition available.

Name:	ter_IncomeTaxesLineItems
Namespace Prefix:	ter_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase decrease in uncertain tax position.

+ References

No definition available.

+ Details

Name:	ter_IncreaseDecreaseInUncertainTaxPosition
Namespace Prefix:	ter_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

+ Details

Name:	us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Per share amount effect of the income tax benefit resulting from the income tax holidays granted by taxing jurisdictions.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

+ Details

Name:	us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income exempt from income tax because of a tax holiday.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32687-109319

+ Details

Name:	us-gaap_IncomeTaxReconciliationTaxHolidays
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount recognized for uncertainty in income taxes classified as current.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LiabilityForUncertainTaxPositionsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant