Name:	ter_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueTableTextBlock
Namespace Prefix:	ter_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Schedule Of Share Based Compensation Arrangement By Share Based Payment Award Options Weighted Average Contractual Terms Table Text Block

No definition available.

Name:	ter_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageContractualTermsTableTextBlock
Namespace Prefix:	ter_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Schedule Of Share Based Compensation Arrangement By Share Based Payment Award Total Shares Available Table Text Block

No definition available.

Name:	ter_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardTotalSharesAvailableTableTextBlock
Namespace Prefix:	ter_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Schedule Of Share Based Payment Award Total Shareholder Return Plan Valuation Assumptions [Table Text Block]

No definition available.

Name:	ter_ScheduleOfShareBasedPaymentAwardTotalShareholderReturnPlanValuationAssumptionsTableTextBlock
Namespace Prefix:	ter_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Schedule Of Weighted Average Stock Options Exercise Price Table Text Block

No definition available.

Name:	ter_ScheduleOfWeightedAverageStockOptionsExercisePriceTableTextBlock
Namespace Prefix:	ter_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Tabular disclosure of activity for outstanding award under share-based payment arrangement excluding share and unit options and nonvested award.

Name:	us-gaap_ScheduleOfOtherShareBasedCompensationActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Tabular disclosure of activity for award under share-based payment arrangement. Includes, but is not limited to, outstanding award at beginning and end of year, granted, exercised, forfeited, and weighted-average grant date fair value.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-SubTopic 10
-Topic 718
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-SubTopic 10
-Topic 718
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Name:	us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Tabular disclosure of number, weighted-average exercise price or conversion ratio, aggregate intrinsic value, and weighted-average remaining contractual term for outstanding restricted stock units that are fully vested and expected to vest. Includes, but is not limited to, unvested restricted stock units for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Subparagraph (e)(1)
-Name Accounting Standards Codification
-Paragraph 2
-Section 50
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Name:	us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedStockUnitsVestedAndExpectedToVestTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Name:	us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Subparagraph (f)(2)
-Name Accounting Standards Codification
-Paragraph 2
-Section 50
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Name:	us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

Disclosure of the number and weighted-average grant date fair value for restricted stock and restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock and restricted stock units that were granted, vested, or forfeited during the year.

No definition available.