STREAM AND ROYALTY INTERESTS, NET - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Cost	$ 3,553,950	$ 3,397,998
Accumulated Depletion	(1,233,696)	(1,058,682)
Impairments	(1,341)
Net	2,318,913	2,339,316
Mount Milligan
Net	554,300
Rainy River
Net	148,500
Pascua-Lama
Net	177,700
Total production stage stream and royalty interests
Cost	3,018,837	2,959,033
Accumulated Depletion	(1,233,696)	(1,058,682)
Impairments	(1,341)
Net	1,783,800	1,900,351
Production stage stream interests
Cost	2,111,423	2,111,423
Accumulated Depletion	(645,705)	(501,026)
Net	1,465,718	1,610,397
Production stage stream interests | Mount Milligan
Cost	790,635	790,635
Accumulated Depletion	(236,352)	(184,091)
Net	554,283	606,544
Production stage stream interests | Pueblo Viejo
Cost	610,404	610,404
Accumulated Depletion	(203,935)	(158,819)
Net	406,469	451,585
Production stage stream interests | Andacollo
Cost	388,182	388,182
Accumulated Depletion	(110,521)	(86,675)
Net	277,661	301,507
Production stage stream interests | Rainy River
Cost	175,727	175,727
Accumulated Depletion	(27,278)	(14,522)
Net	148,449	161,205
Production stage stream interests | Wassa
Cost	146,475	146,475
Accumulated Depletion	(67,619)	(56,919)
Net	78,856	89,556
Production stage royalty interests
Cost	907,414	847,610
Accumulated Depletion	(587,991)	(557,656)
Impairments	(1,341)
Net	318,082	289,954
Production stage royalty interests | Voisey's Bay
Cost	205,724	205,724
Accumulated Depletion	(101,381)	(95,564)
Net	104,343	110,160
Production stage royalty interests | Penasquito
Cost	99,172	99,172
Accumulated Depletion	(44,614)	(40,659)
Net	54,558	58,513
Production stage royalty interests | Holt
Cost	34,612	34,612
Accumulated Depletion	(23,851)	(22,570)
Net	10,761	12,042
Production stage royalty interests | Cortez
Cost	80,681	20,878
Accumulated Depletion	(15,065)	(12,362)
Net	65,616	8,516
Production stage royalty interests | Other
Cost	487,225	487,224
Accumulated Depletion	(403,080)	(386,501)
Impairments	(1,341)
Net	82,804	100,723
Total development stage stream and royalty interests
Cost	219,597	142,793
Net	219,597	142,793
Development stage stream interests | Khoemacau
Cost	136,608
Net	136,608
Development stage stream interests | Other
Cost	12,037	12,038
Net	12,037	12,038
Development stage royalty interests
Cost		130,755
Net		130,755
Development stage royalty interests | Cortez
Cost		59,803
Net		59,803
Development stage royalty interests | Other
Cost	70,952	70,952
Net	70,952	70,952
Exploration stage royalty interests
Cost	315,516	296,172
Net	315,516	296,172
Exploration stage royalty interests | Pascua-Lama
Cost	177,690	177,690
Net	177,690	177,690
Exploration stage royalty interests | Other
Cost	137,826	118,482
Net	$ 137,826	$ 118,482