Represents the amount of annual lease payments.

No definition available.

Name:	intt_AnnualLeasePayments
Namespace Prefix:	intt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase (decrease) in obligation for operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(1)
-SubTopic 20
-Topic 842
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

Name:	us-gaap_IncreaseDecreaseInOperatingLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of periodic reduction over lease term of carrying amount of right-of-use asset from operating lease.

+ References

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_LeaseContractualTermAxis=intt_BuildingLeasesInTheUsTheNetherlandsAndSingaporeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseContractualTermAxis=intt_EnvironmentalTechnologiesInGermanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseContractualTermAxis=intt_ProcessTechnologiesInEuropeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=intt_AutomobileLeaseOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=intt_AutomobileLeaseTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=intt_AutomobileLeasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_LeaseContractualTermAxis=intt_WarehouseAndOfficeSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 9 - Leases (Details Textual) € in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) ft²	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) ft²	Sep. 30, 2023 USD ($)	Sep. 30, 2024 EUR (€) ft²	Mar. 12, 2024 USD ($) ft²	Mar. 12, 2024 EUR (€) ft²	Dec. 31, 2023 USD ($)
Operating Lease, Right-of-Use Asset, Periodic Reduction	$ 356	$ 390	$ 1,041	$ 1,172
Operating Lease, Right-of-Use Asset	11,292		11,292					$ 4,987
Increase (Decrease) in Operating Lease Liability			(1,173)	(1,275)
Operating Lease, Liability	11,596		11,596
Building Leases in the U.S., the Netherlands and Singapore [Member]
Operating Lease, Right-of-Use Asset	5,623		5,623
Operating Lease, Liability	$ 5,623		$ 5,623
Environmental Technologies in Germany [Member]
Operating Lease, Right-of-Use Asset		$ 90		$ 90
Lessee, Operating Lease, Term of Contract (Year)		25 months		25 months
Process Technologies in Europe [Member] \| Automobile Lease, One [Member]
Lessee, Operating Lease, Term of Contract (Year)		36 months		36 months
Process Technologies in Europe [Member] \| Automobile Lease, Two [Member]
Lessee, Operating Lease, Term of Contract (Year)		48 months		48 months
Process Technologies in Europe [Member] \| Automobile Leases [Member]
Operating Lease, Right-of-Use Asset		$ 71		$ 71
Operating Lease, Liability		$ 71		$ 71
Alfamation [Member]
Area of Real Estate Property (Square Foot) \| ft²						51,817	51,817
Annual Lease Payments						$ 284	€ 260
Lessee, Operating Lease, Term of Contract (Year)						6 years	6 years
Alfamation [Member] \| Warehouse and Office Space [Member]
Area of Real Estate Property (Square Foot) \| ft²	51,817		51,817		51,817
Annual Lease Payments \| €					€ 260
Operating Lease, Right-of-Use Asset	$ 1,706		$ 1,706
Increase (Decrease) in Operating Lease Liability			$ 1,706