Investments In Securities Investments In Securities (Schedule of Variable Interest Entities) (Details) - Other investments $ in Thousands	Jun. 30, 2019 USD ($)
Variable Interest Entity [Line Items]
Carrying Value	$ 10,383
Estimated Fair Value	14,549
Maximum Potential Loss	18,398
Tax credit LPs
Variable Interest Entity [Line Items]
Carrying Value	226
Estimated Fair Value	226
Maximum Potential Loss	1,768
Real estate LLCs or LPs
Variable Interest Entity [Line Items]
Carrying Value	5,281
Estimated Fair Value	6,520
Maximum Potential Loss	7,675
Small business investment LPs
Variable Interest Entity [Line Items]
Carrying Value	4,876
Estimated Fair Value	7,803
Maximum Potential Loss	$ 8,955

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.

No definition available.

+ Details

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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=118582676&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=118582676&loc=d3e5728-111685

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Balance Type:	credit
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- 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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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph a
-URI http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685

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- Details

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- Details

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