REVENUE - Property Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue
Revenue	$ 146,441	$ 168,027	$ 308,796	$ 310,616
Stream interests
Disaggregation of Revenue
Revenue	104,879	114,421	210,130	209,767
Stream interests | Mt. Milligan
Disaggregation of Revenue
Revenue	45,627	43,802	88,043	77,606
Stream interests | Pueblo Viejo
Disaggregation of Revenue
Revenue	19,812	26,585	43,076	56,759
Stream interests | Andacollo
Disaggregation of Revenue
Revenue	11,721	27,868	27,395	40,889
Stream interests | Wassa
Disaggregation of Revenue
Revenue	8,248	7,129	15,451	15,902
Stream interests | Khoemacau
Disaggregation of Revenue
Revenue	5,203		7,591
Stream interests | Other.
Disaggregation of Revenue
Revenue	14,268	9,037	28,574	18,611
Royalty interests
Disaggregation of Revenue
Revenue	41,562	53,606	98,666	100,849
Royalty interests | Penasquito
Disaggregation of Revenue
Revenue	9,664	13,399	22,758	26,527
Royalty interests | Cortez
Disaggregation of Revenue
Revenue	8,138	13,739	24,852	22,348
Royalty interests | Other.
Disaggregation of Revenue
Revenue	$ 23,760	$ 26,468	$ 51,056	$ 51,974