XML 137 R118.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Income Taxes - Additional Information (Detail) - USD ($) | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2015 | Oct. 04, 2015 | [3] | Jul. 05, 2015 | [4] | Apr. 05, 2015 | Dec. 31, 2014 | Sep. 28, 2014 | [5],[8] | Jun. 29, 2014 | [5] | Mar. 30, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income tax expense (benefit) from operations, total | $ (8,216,000) | [1],[2] | $ 15,955,000 | $ 29,257,000 | $ 9,651,000 | $ (21,002,000) | [5],[6],[7] | $ 17,721,000 | $ 20,187,000 | $ (2,802,000) | $ 46,647,000 | $ 14,104,000 | $ 36,975,000 |
Effective tax rate |  |  |  |  |  |  |  |  |  |  | 18.40% | 14.80% | 18.30% |
Tax savings due to the tax holiday |  |  |  |  |  |  |  |  |  |  | $ 11,500,000 | $ 13,200,000 | $ 4,700,000 |
Tax savings due to the tax holiday, per share |  |  |  |  |  |  |  |  |  |  | $ 0.05 | $ 0.06 | $ 0.02 |
Tax holiday expiration date |  |  |  |  |  |  |  |  |  |  | December 31, 2015 |  |  |
Accrued interest and penalties | 500,000 |  |  |  |  | 600,000 |  |  |  |  | $ 500,000 | $ 600,000 |  |
Interest and penalties related to income tax |  |  |  |  |  |  |  |  |  |  | 200,000 | 200,000 | $ 200,000 |
Valuation allowance amount decrease/increase |  |  |  |  |  |  |  |  |  |  | 1,300,000 |  |  |
Valuation allowance includes net deferred tax assets | 43,039,000 |  |  |  |  | 41,737,000 |  |  |  |  | 43,039,000 | 41,737,000 |  |
U.S. Federal operating loss carryforwards | 4,870,000 |  |  |  |  |  |  |  |  |  | 4,870,000 |  |  |
Net operating loss carryforward excess tax deductions related to stock based compensation | 0 |  |  |  |  |  |  |  |  |  | 0 |  |  |
Tax credit carryforwards, approximately | 121,200,000 |  |  |  |  |  |  |  |  |  | 121,200,000 |  |  |
Tax credits carryforwards | 44,684,000 |  |  |  |  | 50,554,000 |  |  |  |  | 44,684,000 | 50,554,000 |  |
Unrecognized tax benefits | 36,792,000 |  |  |  |  | $ 30,418,000 |  |  |  |  | 36,792,000 | $ 30,418,000 | $ 21,203,000 | $ 18,666,000
Unrecognized tax benefits, if recognized would impact effective tax rate | 29,200,000 |  |  |  |  |  |  |  |  |  | 29,200,000 |  |  |
Unrecognized tax benefits, if recognized would impact valuation allowance | 7,600,000 |  |  |  |  |  |  |  |  |  | 7,600,000 |  |  |
Decrease in unrecognized tax benefits |  |  |  |  |  |  |  |  |  |  | (7,600,000) |  |  |
Deferred tax liability not been established | 783,000,000 |  |  |  |  |  |  |  |  |  | 783,000,000 |  |  |
United States |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credits carryforwards, business | 43,200,000 |  |  |  |  |  |  |  |  |  | 43,200,000 |  |  |
Tax credits carryforwards | 42,900,000 |  |  |  |  |  |  |  |  |  | 42,900,000 |  |  |
State and Local Jurisdiction |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credits carryforwards | 71,400,000 |  |  |  |  |  |  |  |  |  | $ 71,400,000 |  |  |
Earliest Tax Year | United States |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credit carryforward, expiration date |  |  |  |  |  |  |  |  |  |  | 2017 |  |  |
Earliest Tax Year | State and Local Jurisdiction |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credit carryforward, expiration date |  |  |  |  |  |  |  |  |  |  | 2016 |  |  |
Latest Tax Year | United States |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credit carryforward, expiration date |  |  |  |  |  |  |  |  |  |  | 2035 |  |  |
Latest Tax Year | State and Local Jurisdiction |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credit carryforward, expiration date |  |  |  |  |  |  |  |  |  |  | 2030 |  |  |
Do Not Expire |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Alternative minimum tax credits carryforwards | 6,600,000 |  |  |  |  |  |  |  |  |  | $ 6,600,000 |  |  |
Do Not Expire | State and Local Jurisdiction |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax credits carryforwards | 42,400,000 |  |  |  |  |  |  |  |  |  | 42,400,000 |  |  |
GenRad, Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. Federal operating loss carryforwards | $ 4,900,000 |  |  |  |  |  |  |  |  |  | $ 4,900,000 |  |  |
[1] | In the fourth quarter ended December 31, 2015, Teradyne recorded pension and post retirement net actuarial losses of $17.7 million. See Note B: "Accounting Policies" for a discussion of our accounting policy.
[2] | Restructuring and other includes a $5.3 million fair value adjustment to increase the Universal Robots acquisition contingent consideration, and a $(0.3) million fair value adjustment to decrease the AIT acquisition contingent consideration.
[3] | Restructuring and other includes a $(1.0) million fair value adjustment to decrease the AIT acquisition contingent consideration.
[4] | Restructuring and other includes a $(1.6) million fair value adjustment to decrease the ZTEC acquisition contingent consideration.
[5] | Dividends declared by Teradyne's Board of Directors were paid in the second, third and fourth quarters of 2014.
[6] | In the fourth quarter ended December 31, 2014, Teradyne recorded a goodwill impairment charge of $98.9 million in its Wireless Test segment.
[7] | In the fourth quarter ended December 31, 2014, Teradyne recorded pension and post retirement net actuarial losses of $46.6 million. See Note B: "Accounting Policies" for a discussion of our accounting policy.
[8] | Restructuring and other includes a $(0.6) million fair value adjustment to decrease the ZTEC acquisition contingent consideration.

X
- Definition Deferred tax assets alternative minimum tax credits carryforwards + References No definition available. + Details
Name: | ter_DeferredTaxAssetsAlternativeMinimumTaxCreditsCarryforwards
Namespace Prefix: | ter_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Income Taxes [Line Items] + References No definition available. + Details
Name: | ter_IncomeTaxesLineItems
Namespace Prefix: | ter_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Increase (Decrease) In Unrecognized Tax Benefit + References No definition available. + Details
Name: | ter_IncreaseDecreaseInUnrecognizedTaxBenefit
Namespace Prefix: | ter_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Net operating loss carryforward excess tax deduction related to stock based compensation. + References No definition available. + Details
Name: | ter_NetOperatingLossCarryforwardExcessTaxDeductionRelatedToStockBasedCompensation
Namespace Prefix: | ter_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Tax Credit Carryforward, Expiration Year + References No definition available. + Details
Name: | ter_TaxCreditCarryforwardExpirationYear
Namespace Prefix: | ter_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unrecognized tax benefits, if recognized would impact valuation allowance. + References No definition available. + Details
Name: | ter_UnrecognizedTaxBenefitsIfRecognizedWouldImpactValuationAllowance
Namespace Prefix: | ter_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 20 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51675352&loc=d3e28680-109314 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319 + Details
Name: | us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Carryforwards -URI http://asc.fasb.org/extlink&oid=6506874 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319 + Details
Name: | us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible general business tax credit carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319 + Details
Name: | us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsGeneralBusiness
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319 + Details
Name: | us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of deferred tax liability not recognized because of the exceptions to comprehensive recognition of deferred taxes related to undistributed earnings of foreign subsidiaries. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331 + Details
Name: | us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfForeignSubsidiaries
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateContinuingOperations
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
Name: | us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Income Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6515339 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 11.C) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330215-122817 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 11 -Section C + Details
Name: | us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The date on which the special tax status will terminate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 11.C) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330215-122817 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 11 -Section C + Details
Name: | us-gaap_IncomeTaxHolidayTerminationDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 + Details
Name: | us-gaap_IncomeTaxReconciliationTaxHolidays
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Carryforwards -URI http://asc.fasb.org/extlink&oid=6506874 + Details
Name: | us-gaap_TaxCreditCarryforwardAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Unrecognized Tax Benefit -URI http://asc.fasb.org/extlink&oid=6527854 + Details
Name: | us-gaap_UnrecognizedTaxBenefits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e32123-109318 + Details
Name: | us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_DomesticCountryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxPeriodAxis=us-gaap_EarliestTaxYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxPeriodAxis=us-gaap_LatestTaxYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TaxPeriodAxis=ter_DoNotExpireMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ter_GenradIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |