STREAM AND ROYALTY INTERESTS, NET - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Jun. 30, 2019
Cost	$ 3,505,832	$ 3,397,998
Accumulated Depletion	(1,188,419)	(1,058,682)
Net	2,317,413	2,339,316
Mount Milligan
Net	572,300
Rainy River
Net	152,600
Total production stage stream and royalty interests
Cost	3,018,836	2,959,033
Accumulated Depletion	(1,188,419)	(1,058,682)
Net	1,830,417	1,900,351
Production stage stream interests
Cost	2,111,423	2,111,423
Accumulated Depletion	(607,910)	(501,026)
Net	1,503,513	1,610,397
Production stage stream interests | Mount Milligan
Cost	790,635	790,635
Accumulated Depletion	(218,378)	(184,091)
Net	572,257	606,544
Production stage stream interests | Pueblo Viejo
Cost	610,404	610,404
Accumulated Depletion	(193,109)	(158,819)
Net	417,295	451,585
Production stage stream interests | Andacollo
Cost	388,182	388,182
Accumulated Depletion	(107,501)	(86,675)
Net	280,681	301,507
Production stage stream interests | Rainy River
Cost	175,727	175,727
Accumulated Depletion	(23,176)	(14,522)
Net	152,551	161,205
Production stage stream interests | Wassa and Prestea
Cost	146,475	146,475
Accumulated Depletion	(65,746)	(56,919)
Net	80,729	89,556
Production stage royalty interests
Cost	907,413	847,610
Accumulated Depletion	(580,509)	(557,656)
Net	326,904	289,954
Production stage royalty interests | Voisey's Bay
Cost	205,724	205,724
Accumulated Depletion	(100,140)	(95,564)
Net	105,584	110,160
Production stage royalty interests | Penasquito
Cost	99,172	99,172
Accumulated Depletion	(43,744)	(40,659)
Net	55,428	58,513
Production stage royalty interests | Holt
Cost	34,612	34,612
Accumulated Depletion	(23,796)	(22,570)
Net	10,816	12,042
Production stage royalty interests | Cortez
Cost	80,681	20,878
Accumulated Depletion	(13,702)	(12,362)
Net	66,979	8,516
Production stage royalty interests | Other
Cost	487,224	487,224
Accumulated Depletion	(399,127)	(386,501)
Net	88,097	100,723
Total development stage stream and royalty interests
Cost	171,630	142,793
Net	171,630	142,793
Development stage stream interests | Khoemacau
Cost	88,641
Net	88,641
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	315,366	296,172
Net	315,366	296,172
Exploration stage royalty interests | Pascua-Lama
Cost	177,690	177,690
Net	177,690	177,690
Exploration stage royalty interests | Other
Cost	137,676	118,482
Net	$ 137,676	$ 118,482