ACQUISITIONS AND DISPOSITIONS - Cote (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 07, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Significant Acquisitions and Disposals [Line Items]
Payment to acquire interest		$ 168,147	$ 155,985	$ 1,055
Stream and royalty interest		$ 2,262,158	$ 2,318,913
Cote Gold Project
Significant Acquisitions and Disposals [Line Items]
Net smelter return (NSR) (as a percent)	1.00%
Royalty covering current reserves (as a percent)	70.00%
Payment to acquire interest	$ 75,000
Stream and royalty interest	$ 75,000
Cote Gold Project | Cote Gold Joint Venture | Cote Gold Project
Significant Acquisitions and Disposals [Line Items]
Joint venture ownership interest (as a percent)	92.50%
Cote Gold Project | IAMGOLD Corporation | Cote Gold Joint Venture
Significant Acquisitions and Disposals [Line Items]
Joint venture ownership interest (as a percent)	70.00%
Cote Gold Project | Sumitomo Metal Mining | Cote Gold Joint Venture
Significant Acquisitions and Disposals [Line Items]
Joint venture ownership interest (as a percent)	30.00%
Cote Gold Project | Third Party | Cote Gold Project
Significant Acquisitions and Disposals [Line Items]
Joint venture ownership interest (as a percent)	7.50%