Investments In Securities and Fair Value (Schedule of Variable Interest Entities) (Details) - Other investments $ in Thousands	Mar. 31, 2022 USD ($)
Variable Interest Entity, Not Primary Beneficiary [Line Items]
Carrying Value	$ 12,927
Estimated Fair Value	14,179
Maximum Potential Loss (a)	21,496
Tax Credit LPs
Variable Interest Entity, Not Primary Beneficiary [Line Items]
Carrying Value	276
Estimated Fair Value	276
Maximum Potential Loss (a)	1,768
Real Estate LLCs or LPs
Variable Interest Entity, Not Primary Beneficiary [Line Items]
Carrying Value	3,887
Estimated Fair Value	5,098
Maximum Potential Loss (a)	5,408
Small Business Investment LPs
Variable Interest Entity, Not Primary Beneficiary [Line Items]
Carrying Value	8,764
Estimated Fair Value	8,805
Maximum Potential Loss (a)	$ 14,320

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary

No definition available.

+ Details

Name:	itic_VariableInterestEntityNonconsolidatedCarryingAmount
Namespace Prefix:	itic_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Estimated fair value amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

No definition available.

+ Details

Name:	itic_VariableInterestEntityNonconsolidatedFairValueAmountAssets
Namespace Prefix:	itic_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123419778&loc=d3e5747-111685

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=123419778&loc=d3e5728-111685

+ Details

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

- 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

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Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

Name:	srt_ConsolidatedEntitiesAxis=itic_VariableInterestEntityNotPrimaryBeneficiaryTaxCreditLpMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_ConsolidatedEntitiesAxis=itic_VariableInterestEntityNotPrimaryBeneficiaryRealEstateLLCorLPMemberMember
Namespace Prefix:
Data Type:	na
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- Details

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