STREAM AND ROYALTY INTERESTS, NET (Details) $ in Thousands	6 Months Ended
	Dec. 31, 2019 USD ($) oz	Jun. 30, 2019 USD ($)
Stream and royalty interests, net | $	$ 2,333,091	$ 2,339,316
Mount Milligan
Gold streaming interest (as a percent)	35.00%
Copper streaming interest (as a percent)	18.75%
Stream and royalty interests, net | $	$ 589,300
Rainy River
Stream and royalty interests, net | $	$ 155,300
Gold delivered (in ounces) | oz	32,200
Silver delivered (in ounces) | oz	332,300
Rainy River | Initial Royalty
Gold streaming interest (as a percent)	6.50%
Silver production acquired (as a percent)	60.00%
Gold delivered (in ounces) | oz	230,000
Silver delivered (in ounces) | oz	3,100,000
Rainy River | Subsequent Royalty
Gold streaming interest (as a percent)	3.25%
Silver production acquired (as a percent)	30.00%
El Toqui
Stream and royalty interests, net | $	$ 1,300