SEGMENT INFORMATION (Details) $ in Thousands	12 Months Ended
	Jun. 30, 2021 USD ($) segment	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Long Lived Assets and Pre-Tax Income by Geographical Information
Number of reportable segments | segment	2
Stream and royalty interest	$ 2,262,158	$ 2,318,913
Revenue	615,856	498,819	$ 423,056
Cost of sales	92,898	83,890	77,535
Production taxes	6,743	3,824	4,112
Depletion	183,213	175,047	162,856
Total segment gross profit	333,002	236,058	178,553
Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	876,759	892,587
Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	366,698	406,469
Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	480,720	501,583
Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	291,433	215,784
Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	66,867	75,951
United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	112,817	159,445
Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	28,117	30,006
Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	38,747	37,088
Stream interests
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	1,550,664	1,614,363
Revenue	423,989	359,868	305,824
Cost of sales	92,898	83,890	77,535
Depletion	150,594	144,678	127,770
Total segment gross profit	180,497	131,300	100,519
Stream interests | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	624,212	702,732
Revenue	190,537	158,736	123,152
Stream interests | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	366,698	406,469
Revenue	115,583	96,978	82,844
Stream interests | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	256,604	277,661
Revenue	82,164	74,219	69,264
Stream interests | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	291,112	215,463
Revenue	35,705	29,935	30,564
Stream interests | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	12,038	12,038
Royalty interests
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	711,494	704,550
Revenue	191,867	138,951	117,232
Production taxes	6,743	3,824	4,112
Depletion	32,619	30,369	35,086
Total segment gross profit	152,505	104,758	78,034
Royalty interests | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	252,547	189,855
Revenue	31,671	30,524	32,602
Royalty interests | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	224,116	223,922
Royalty interests | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	321	321
Revenue	2,801	2,575	1,416
Royalty interests | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	66,867	75,951
Revenue	58,212	32,731	27,224
Royalty interests | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	112,817	159,445
Revenue	68,611	48,692	34,845
Royalty interests | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	28,117	30,006
Revenue	21,466	15,252	12,806
Royalty interests | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	26,709	25,050
Revenue	$ 9,106	$ 9,177	$ 8,339