INVESTMENT IN MARKETABLE SECURITIES - Additional information (Details) - USD ($)	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Debt and Equity Securities, FV-NI [Line Items]
Trading Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	$ 11,088,000	$ 10,819,000
Percentage Of Investment Marketable Securities	7.00%	7.00%
Comstock Mining Inc [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	$ 10,900,000	$ 10,646,000