Note 3 - Acquisition - Intangible Assets (Details) - Alfamation [Member] - USD ($) $ in Thousands		3 Months Ended
Mar. 12, 2024	Mar. 31, 2024
Finite-lived intangible assets	$ 9,688	$ 9,688
Useful life (Year)	9 years 10 months 24 days
Indefinite-lived intangible assets		$ 3,399
Total intangible assets	$ 13,087
Trade Names [Member]
Indefinite-lived intangible assets	3,399
Customer Relationships [Member]
Finite-lived intangible assets	$ 5,949
Useful life (Year)	15 years
Technology-Based Intangible Assets [Member]
Finite-lived intangible assets	$ 340
Useful life (Year)	10 years
Customer-Related Intangible Assets [Member]
Finite-lived intangible assets	$ 3,399
Useful life (Year)	1 year

Amount of increase in assets, excluding financial assets, lacking physical substance, from an acquisition.

No definition available.

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Namespace Prefix:	intt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 985
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481283/985-20-50-2

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-1

+ Details

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

- Definition

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, from an acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-2

+ Details

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Period Type:	duration

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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- Details

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