Business Acquisition Contingent Consideration Percentage

No definition available.

Name:	ter_BusinessAcquisitionContingentConsiderationPercentage
Namespace Prefix:	ter_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow, not made soon after acquisition date of business combination, to settle contingent consideration liability up to amount recognized at acquisition date, including, but not limited to, measurement period adjustment and less amount paid soon after acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

Name:	us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ter_UniversalRobotsMember
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:

Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2017	Jul. 03, 2016	Jul. 02, 2017	Jul. 03, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			$ 1,050	$ 11,697
Increase(decrease)in contingent consideration		$ 1,300	2,133	2,478
Universal Robots
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration				$ 15,000
EBITDA contingent consideration amount, percentage		100.00%		100.00%
Increase(decrease)in contingent consideration	$ 1,500	$ 800	2,100	$ 1,900
Avionics Interface Technologies, LLC
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments of contingent consideration			$ 1,100
Increase(decrease)in contingent consideration		$ 600		$ 600