XML 73 R60.htm IDEA: XBRL DOCUMENT
v3.21.2

Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands | Oct. 03, 2021 | Dec. 31, 2020
--- | --- | ---
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | $ 328,741 | $ 601,976
Available-for-sale marketable securities, Unrealized Gain | 6,138 | 9,077
Available-for-sale marketable securities, Unrealized (Loss) | (594) | (213)
Available-for-sale marketable securities, Fair Market Value | 334,285 | 610,840
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | 63,447 | 70,418
Marketable securities |  |
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | 233,327 | 522,228
Available-for-sale marketable securities, Unrealized Gain | 92 | 92
Available-for-sale marketable securities, Unrealized (Loss) | (22) | (40)
Available-for-sale marketable securities, Fair Market Value | 233,397 | 522,280
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | 28,773 | 61,806
Long-term marketable securities |  |
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | 95,414 | 79,748
Available-for-sale marketable securities, Unrealized Gain | 6,046 | 8,985
Available-for-sale marketable securities, Unrealized (Loss) | (572) | (173)
Available-for-sale marketable securities, Fair Market Value | 100,888 | 88,560
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | $ 34,674 | $ 8,612

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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