Name:	INTG_MarketableSecuritiesUnrealizedGainsLoss
Namespace Prefix:	INTG_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27357-111563

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

Amount of unrealized gain on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Name:	us-gaap_DebtSecuritiesTradingUnrealizedGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of unrealized and realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI).

No definition available.

Name:	us-gaap_MarketableSecuritiesGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI).

No definition available.