INCOME TAXES - Deferred (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Deferred tax assets:
Stock-based compensation	$ 1,118	$ 805
Net operating losses	56	1,933
Foreign tax credits	11,125	11,172
Other	7,960	7,346
Total deferred tax assets	20,259	21,256
Valuation allowance	(12,764)	(12,811)
Net deferred tax assets	7,495	8,445
Deferred tax liabilities:
Mineral property basis	(74,360)	(74,274)
Unrealized foreign exchange gains	(582)	(664)
2019 Notes		(2,631)
Investment in Peak Gold joint venture	(4,353)	(4,359)
Other	(150)	(213)
Total deferred tax liabilities	(79,445)	(82,141)
Total net deferred taxes	(71,950)	(73,696)
Net operating loss carry forwards	$ 200	$ 7,100
Tax carryforward period	20 years