SEGMENT INFORMATION - Reconciliation gross profit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
SEGMENT INFORMATION
Total segment gross profit	$ 78,083	$ 62,510	$ 239,732	$ 183,012
Costs and expenses
General and administrative expenses	6,932	9,551	21,175	23,658
Exploration costs		565	563	4,705
Depreciation and amortization	94	113	265	280
Gain on sale of Peak Gold JV interest			(33,906)
Operating income	71,057	52,281	251,635	154,369
Fair value changes in equity securities	1,902	(3,819)	4,060	(4,972)
Interest and other income	733	620	1,767	1,621
Interest and other expense	(1,820)	(2,088)	(5,274)	(7,139)
Income before income taxes	$ 71,872	$ 46,994	$ 252,188	$ 143,879