XML 70 R56.htm IDEA: XBRL DOCUMENT
v3.20.2

Financial Instruments - Additional Information (Detail) - USD ($) | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Sep. 27, 2020 | Sep. 29, 2019 | Sep. 27, 2020 | Sep. 29, 2019 | Dec. 31, 2019 | Jun. 28, 2020
Financial Instruments and Fair Value [Line Items] |  |  |  |  |  |
Available-for-sale securities, realized gain | $ 1,100,000 | $ 500,000 | $ 4,100,000 | $ 700,000 |  |
Available-for-sale securities, realized loss | 100,000 |  | 300,000 | 200,000 |  |
Fair market value of investments with unrealized losses less than one year | 24,400,000 |  | 24,400,000 |  | $ 23,600,000 |
Unrealized Gain (loss) on contracts | (1,200,000) | (1,500,000) | 400,000 | 3,400,000 |  |
Equity securities unrealized gain loss | 2,000,000.0 | $ 100,000 | 5,700,000 | 3,800,000 |  |
Equity securities unrealized (gains) loss |  |  | 6,000,000.0 | $ 200,000 |  |
Debt Mutual Funds |  |  |  |  |  |
Financial Instruments and Fair Value [Line Items] |  |  |  |  |  |
Available for sale securities with out contractual maturity date | 6,900 |  | 6,900 |  |  |
Mobile Industrial Robots (MiR) |  |  |  |  |  |
Financial Instruments and Fair Value [Line Items] |  |  |  |  |  |
Maximum amount of contingent consideration paid for acquisition | 65,800,000 |  | 65,800,000 |  |  |
Autoguide LLC [Member] |  |  |  |  |  |
Financial Instruments and Fair Value [Line Items] |  |  |  |  |  |
Maximum amount of contingent consideration paid for acquisition | $ 106,900,000 |  | 106,900,000 |  |  | $ 106,900,000
Foreign Exchange Contracts |  |  |  |  |  |
Financial Instruments and Fair Value [Line Items] |  |  |  |  |  |
Unrealized Gain (loss) on contracts |  |  | $ 111,500,000 |  | $ 144,900,000 |

X
- Definition Financial Instruments and Fair Value [Line Items] + References No definition available. + Details
Name: | ter_FinancialInstrumentsAndFairValueLineItems
Namespace Prefix: | ter_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Foreign Currency Transaction (Loss), Unrealized + References No definition available. + Details
Name: | ter_ForeignCurrencyTransactionlossUnrealized
Namespace Prefix: | ter_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 + Details
Name: | us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117546-209714 + Details
Name: | us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount before tax of foreign currency transaction unrealized gain (loss) recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30690-110894 + Details
Name: | us-gaap_ForeignCurrencyTransactionGainLossUnrealized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=ter_DebtMutualFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |