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

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

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

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

+ 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_EnvironmentalTechnologiesInGermanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Note 8 - Leases (Details Textual) - USD ($)	3 Months Ended
Note 8 - Leases (Details Textual) - USD ($)	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Mar. 31, 203
Operating Lease, Right-of-Use Asset, Periodic Reduction	$ 391,000	$ 309,000
Operating Lease, Right-of-Use Asset	5,506,000		$ 5,770,000
Environmental Technologies in Germany [Member]
Lessee, Operating Lease, Term of Contract (Month)				25 months
Operating Lease, Right-of-Use Asset	$ 90,000
Process Technologies [Member]
Lessee, Operating Lease, Term of Contract (Month)	36 months
Operating Lease, Right-of-Use Asset	$ 30