Option term description.

No definition available.

Name:	INTG_OptionTermDescription
Namespace Prefix:	INTG_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Plan term.

+ References

No definition available.

+ Details

Name:	INTG_PlanTerm
Namespace Prefix:	INTG_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment option shares issued.

+ References

No definition available.

+ Details

Name:	INTG_ShareBasedCompensationArrangementByShareBasedPaymentOptionSharesIssued
Namespace Prefix:	INTG_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment options surrendered.

+ References

No definition available.

+ Details

Name:	INTG_ShareBasedCompensationArrangementByShareBasedPaymentOptionsSurrendered
Namespace Prefix:	INTG_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Schedule of stock based compensation.

+ References

No definition available.

+ Details

Name:	INTG_StockBasedCompensationLineItems
Namespace Prefix:	INTG_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of noncash expense for share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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

- Definition

Number of share options (or share units) exercised during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PlanNameAxis=INTG_TwoThousandTenIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=INTG_JohnVWinfieldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_StockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock Based Compensation Plans (Details Narrative) - USD ($)		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 25, 2020	Mar. 31, 2020	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2020
Stock Based Compensation [Line Items]
Stock based compensation				$ 5,000	$ 9,000	$ 10,000	$ 17,000
Unamortized compensation related to stock option				$ 8,000		$ 8,000
Recognized weighted average period						1 year 2 months 1 day
Share based compensation arrangement by share based payment awards exercised
2010 Incentive Plan [Member]
Stock Based Compensation [Line Items]
Plan term	20 years
2010 Incentive Plan [Member] \| Minimum [Member]
Stock Based Compensation [Line Items]
Plan term	10 years
2010 Incentive Plan [Member] \| Maximum [Member]
Stock Based Compensation [Line Items]
Plan term	16 years
John V. Winfield [Member] \| 2010 Incentive Plan [Member]
Stock Based Compensation [Line Items]
Stock based compensation		$ 116,000
Share based compensation arrangement by share based payment option shares issued	100,000
Option term description	Options granted to John Winfield on March 16, 2010 from ten years to sixteen years so that these options will terminate on March 16, 2026 instead of on March 16, 2020
John V. Winfield [Member] \| Vested Incentive Stock Options [Member]
Stock Based Compensation [Line Items]
Share based compensation arrangement by share based payment awards exercised			26,805
Share based compensation arrangement by share based payment options surrendered			17,439
Share based compensation arrangement by share based payment option shares issued			9,366