INVESTMENT IN MARKETABLE SECURITIES (Details Textual) (USD $)	6 Months Ended	12 Months Ended
Dec. 31, 2014	Jun. 30, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	$ 1,881,000	$ 1,615,000

Amount of unrealized loss on investments in trading securities that have been in a loss position for twelve months or longer.

No definition available.

Name:	intg_TradingSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLoss
Namespace Prefix:	intg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration