SEGMENT INFORMATION - Geographical (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Long Lived Assets and Pre-Tax Income by Geographical Information
Number of reportable segments | segment			2
Total stream and royalty interests, net	$ 3,021,324		$ 3,021,324		$ 3,075,574
Revenue	193,837	$ 138,617	516,835	$ 453,051
Cost of sales	27,192	21,351	73,116	69,738
Production taxes	1,520	1,671	4,550	4,934
Depletion	36,091	39,989	110,433	124,501
Segment gross profit	129,034	75,606	328,736	253,878
Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,088,992		1,088,992		1,076,298
Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	303,954		303,954		311,050
Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	242,699		242,699		264,850
Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	438,625		438,625		446,745
United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	778,496		778,496		794,891
Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	35,629		35,629		41,803
Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	19,908		19,908		21,288
Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	113,021		113,021		118,649
Stream interest
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,275,771		1,275,771		1,351,616
Revenue	133,052	98,978	358,531	319,982
Cost of sales	27,192	21,351	73,116	69,738
Production taxes	0	0	0	0
Depletion	26,674	30,433	80,199	93,537
Segment gross profit	79,186	47,194	205,216	156,707
Stream interest | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	428,042		428,042		461,398
Revenue	66,372	42,577	173,737	150,405
Stream interest | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	303,954		303,954		311,050
Revenue	26,585	16,688	64,147	62,586
Stream interest | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	242,378		242,378		264,529
Revenue	19,973	18,092	59,470	54,394
Stream interest | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	214,509		214,509		222,629
Revenue	9,652	14,644	31,949	35,401
Stream interest | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0		0
Stream interest | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0		0
Stream interest | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0		0
Stream interest | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	86,888		86,888		92,010
Revenue	10,470	6,977	29,228	17,196
Royalty interest
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,745,553		1,745,553		1,723,958
Revenue	60,785	39,639	158,304	133,069
Cost of sales	0	0	0	0
Production taxes	1,520	1,671	4,550	4,934
Depletion	9,417	9,556	30,234	30,964
Segment gross profit	49,848	28,412	123,520	97,171
Royalty interest | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	660,950		660,950		614,900
Revenue	5,269	3,090	13,435	9,585
Royalty interest | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0		0
Royalty interest | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	321		321		321
Royalty interest | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	224,116		224,116		224,116
Royalty interest | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	778,496		778,496		794,891
Revenue	34,131	28,237	83,484	85,082
Royalty interest | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	35,629		35,629		41,803
Revenue	10,853	1,964	34,509	19,413
Royalty interest | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	19,908		19,908		21,288
Revenue	7,476	4,696	19,498	13,874
Royalty interest | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	26,133		26,133		$ 26,639
Revenue	$ 3,056	$ 1,652	$ 7,378	$ 5,115