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BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Details Textual)
9 Months Ended
Mar. 31, 2015
Basis Of Presentation And Significant Accounting Policies [Line Items]  
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest 93.00%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
Santa Fe [Member]  
Basis Of Presentation And Significant Accounting Policies [Line Items]  
Business Acquisition, Percentage of Voting Interests Acquired 85.30%us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
/ dei_LegalEntityAxis
= intg_SantaFeMember
Percentage Of Voting Shares In Common Stock 4.00%intg_PercentageOfVotingSharesInCommonStock
/ dei_LegalEntityAxis
= intg_SantaFeMember
Portsmouth [Member]  
Basis Of Presentation And Significant Accounting Policies [Line Items]  
Equity Method Investment, Ownership Percentage 68.80%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= intg_PortsmouthMember
Noncontrolling Interest, Ownership Percentage by Parent 13.10%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= intg_PortsmouthMember