STREAM AND ROYALTY INTERESTS, NET - Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jun. 30, 2020
Cost	$ 3,559,270	$ 3,553,950
Accumulated Depletion	(1,327,290)	(1,233,696)
Impairments		(1,341)
Net	2,231,980	2,318,913
Other
Cost		137,826
Net		137,826
Total production stage stream and royalty interests
Cost	3,018,290	3,018,837
Accumulated Depletion	(1,327,290)	(1,233,696)
Impairments		(1,341)
Net	1,691,000	1,783,800
Production stage stream interests
Cost	2,111,424	2,111,423
Accumulated Depletion	(724,959)	(645,705)
Net	1,386,465	1,465,718
Production stage stream interests | Mount Milligan
Cost	790,635	790,635
Accumulated Depletion	(270,370)	(236,352)
Net	520,265	554,283
Production stage stream interests | Pueblo Viejo
Cost	610,405	610,404
Accumulated Depletion	(226,083)	(203,935)
Net	384,322	406,469
Production stage stream interests | Andacollo
Cost	388,182	388,182
Accumulated Depletion	(120,847)	(110,521)
Net	267,335	277,661
Production stage stream interests | Rainy River
Cost	175,727	175,727
Accumulated Depletion	(34,820)	(27,278)
Net	140,907	148,449
Production stage stream interests | Wassa
Cost	146,475	146,475
Accumulated Depletion	(72,839)	(67,619)
Net	73,636	78,856
Production stage royalty interests
Cost	906,866	907,414
Accumulated Depletion	(602,331)	(587,991)
Impairments		(1,341)
Net	304,535	318,082
Production stage royalty interests | Voisey's Bay
Cost	205,724	205,724
Accumulated Depletion	(104,850)	(101,381)
Net	100,874	104,343
Production stage royalty interests | Penasquito
Cost	99,172	99,172
Accumulated Depletion	(47,263)	(44,614)
Net	51,909	54,558
Production stage royalty interests | Cortez
Cost	80,681	80,681
Accumulated Depletion	(16,418)	(15,065)
Net	64,263	65,616
Production stage royalty interests | Other
Cost	521,289	521,837
Accumulated Depletion	(433,800)	(426,931)
Impairments		(1,341)
Net	87,489	93,565
Total development stage stream and royalty interests
Cost	262,037	219,597
Net	262,037	219,597
Development stage stream interests | Khoemacau
Cost	180,220	136,608
Net	180,220	136,608
Development stage stream interests | Other
Cost	12,037	12,037
Net	12,037	12,037
Development stage royalty interests
Cost		70,952
Net		70,952
Development stage royalty interests | Other
Cost	69,780	70,952
Net	69,780	70,952
Exploration stage royalty interests
Cost	278,943	315,516
Net	278,943	315,516
Exploration stage royalty interests | Pascua-Lama
Cost	177,690	177,690
Net	177,690	$ 177,690
Exploration stage royalty interests | Other
Cost	101,253
Net	$ 101,253