BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Details Textual)	6 Months Ended
Dec. 31, 2015
Basis Of Presentation And Significant Accounting Policies [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	93.00%
Portsmouth [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Equity Method Investment, Ownership Percentage	68.80%
Noncontrolling Interest, Ownership Percentage by Parent	13.10%
Santa Fe [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	85.60%
Percentage Of Voting Shares In Common Stock	4.00%

No definition available.

Name:	intg_BasisOfPresentationAndSignificantAccountingPoliciesLineItems
Namespace Prefix:	intg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting shares in common stock during the period.

+ References

No definition available.

+ Details

Name:	intg_PercentageOfVotingSharesInCommonStock
Namespace Prefix:	intg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611443-123010

+ Details

Name:	us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=intg_PortsmouthMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=intg_SantaFeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: