Note 7 - Leases - Supplemental Cash Flow Information (Details) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Accounting Standards Update 2016-02 [Member]
Non-cash decrease in operating lease liabilities and right-of-use assets as a result of lease modifications	$ 486

Represents the non-cash decrease in operating lease liabilities and right-of-use assets.

No definition available.

Name:	intt_DecreaseInOperatingLeaseLiabilitiesAndRightOfUseAssetsNonCash
Namespace Prefix:	intt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration