SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)
Long Lived Assets and Pre-Tax Income by Geographical Information
Number of reportable segments | segment	2
Stream and royalty interest	$ 2,476,630		$ 2,262,158
Revenue	174,431	$ 146,880
Cost of sales	27,230	21,902
Production taxes	2,054	1,355
Depletion	50,519	46,214
Total segment gross profit	94,628	77,409
Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	1,014,638		876,759
Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	358,237		366,698
Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	477,637		480,720
Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	288,256		291,433
Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	63,687		66,867
United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	110,153		112,817
Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	27,788		28,117
Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	136,234		38,747
Stream interests
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	1,608,736		1,550,664
Revenue	115,921	106,503
Cost of sales	27,230	21,902
Depletion	41,922	39,027
Total segment gross profit	46,769	45,574
Stream interests | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	599,425		624,212
Revenue	64,031	41,586
Stream interests | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	358,237		366,698
Revenue	27,198	31,270
Stream interests | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	253,521		256,604
Revenue	11,601	23,509
Stream interests | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	287,935		291,112
Revenue	8,679	10,138
Stream interests | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	109,618		12,038
Revenue	4,412
Royalty interests
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	867,894		711,494
Revenue	58,510	40,377
Production taxes	2,054	1,355
Depletion	8,597	7,187
Total segment gross profit	47,859	31,835
Royalty interests | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	415,213		252,547
Revenue	6,402	7,410
Royalty interests | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	224,116		224,116
Royalty interests | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	321		321
Revenue	602	750
Royalty interests | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	63,687		66,867
Revenue	15,427	11,577
Royalty interests | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	110,153		112,817
Revenue	27,080	13,698
Royalty interests | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	27,788		28,117
Revenue	6,917	4,542
Royalty interests | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Stream and royalty interest	26,616		$ 26,709
Revenue	$ 2,082	$ 2,400