Fair Value Inputs, Probability of Achieving Target

No definition available.

Name:	ter_FairValueInputsProbabilityOfAchievingTarget
Namespace Prefix:	ter_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of liability recognized arising from contingent consideration in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

+ Details

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

- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ter_UniversalRobotsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=ter_MonteCarloSimulationValuationModelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=ter_RevenueOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=ter_RevenueTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_IncomeApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=ter_RevenueThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ter_AvionicsInterfaceTechnologiesLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jul. 03, 2016	Jun. 11, 2015
Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration		$ 31,600
Monte Carlo simulation model \| Revenue for the period July 1, 2015-December 31, 2017 \| Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Target achievement, volatility	15.60%
Discount Rate	4.00%
Monte Carlo simulation model \| Revenue for the period July 1, 2015-December 31, 2018 \| Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Target achievement, volatility	15.60%
Discount Rate	4.00%
Monte Carlo simulation model \| Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration	$ 6,942
Monte Carlo simulation model \| Significant Unobservable Inputs (Level 3) \| Universal Robots
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration	$ 16,922
Income Approach Valuation Technique \| Revenue for calendar year 2016 \| Avionics Interface Technologies, LLC
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Discount Rate	4.00%
Target achievement, probability	100.00%
Income Approach Valuation Technique \| Significant Unobservable Inputs (Level 3) \| Avionics Interface Technologies, LLC
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Contingent consideration	$ 1,050