SEGMENT INFORMATION - Geographical (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)	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	$ 3,038,495		$ 3,075,574
Revenue	148,902	$ 170,392
Cost of sales	21,751	25,020
Production taxes	1,449	1,989
Depletion	38,683	46,214
Segment gross profit	87,019	97,169
Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,064,038		1,076,298
Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	256,025		264,850
Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	308,814		311,050
Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	443,508		446,745
United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	789,467		794,891
Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	39,245		41,803
Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	20,961		21,288
Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	116,437		118,649
Stream interest
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,325,319		1,351,616
Revenue	102,528	114,990
Cost of sales	21,751	25,020
Production taxes	0	0
Depletion	27,401	33,752
Segment gross profit	53,376	56,218
Stream interest | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	451,610		461,398
Revenue	44,705	56,981
Stream interest | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	255,704		264,529
Revenue	19,101	17,539
Stream interest | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	308,814		311,050
Revenue	17,760	22,358
Stream interest | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	219,392		222,629
Revenue	11,689	12,934
Stream interest | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0
Stream interest | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0
Stream interest | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0
Stream interest | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	89,799		92,010
Revenue	9,273	5,178
Royalty interest
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	1,713,176		1,723,958
Revenue	46,374	55,402
Cost of sales	0	0
Production taxes	1,449	1,989
Depletion	11,282	12,462
Segment gross profit	33,643	40,951
Royalty interest | Canada
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	612,428		614,900
Revenue	5,131	6,591
Royalty interest | Africa
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	321		321
Royalty interest | Dominican Republic
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	0		0
Royalty interest | Chile
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	224,116		224,116
Royalty interest | United States
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	789,467		794,891
Revenue	24,079	33,581
Royalty interest | Mexico
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	39,245		41,803
Revenue	10,768	9,295
Royalty interest | Australia
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	20,961		21,288
Revenue	4,975	4,099
Royalty interest | Rest of world
Long Lived Assets and Pre-Tax Income by Geographical Information
Total stream and royalty interests, net	26,638		$ 26,639
Revenue	$ 1,421	$ 1,836