ACQUISITIONS AND DISPOSITIONS - 2019 Acquisitions (Details) $ in Thousands, oz in Millions					1 Months Ended		6 Months Ended		7 Months Ended	12 Months Ended			15 Months Ended
	Oct. 08, 2021 USD ($)	Apr. 07, 2021 USD ($) oz T	Mar. 30, 2020 USD ($)	Feb. 25, 2019 oz	Nov. 30, 2019 USD ($)	Aug. 31, 2019 USD ($) payment shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Oct. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jan. 31, 2021 USD ($)	Dec. 31, 2021 $ / shares
Acquisitions
Acquisition consideration paid							$ 281,066	$ 48,832		$ 168,147	$ 155,985	$ 1,055
Investment value							1,700			3,100	17,900
Cost							$ 3,899,867			$ 3,618,802	$ 3,553,950
TriStar
Acquisitions
Stock that can be purchased by warrants (in shares) | shares							19,640,000
CDS
Acquisitions
Net smelter return (NSR) (as a percent)						1.50%
Acquisition consideration paid			$ 1,500		$ 1,500	$ 4,500
Cost						$ 7,500
Number of installments | payment						3
CDS | TriStar
Acquisitions
Stock that can be purchased by warrants (in shares) | shares						19,640,000	19,640,000
Investment value							$ 1,700
Exercise price of warrants | $ / shares														$ 0.25
Term of warrants							3 years
Khoemacau
Acquisitions
Acquisition consideration paid	$ 15,900	$ 10,600							$ 26,500				$ 212,000
Silver production acquired (as a percent)		90.00%		80.00%			90.00%
Silver production after threshold (as a percent)		45.00%		40.00%
Rate reduction threshold | oz		36.0		32.0
Spot price paid (as a percent)		20.00%
Increased level of throughput (as a percent)		30.00%
Throughput levels | T		14,300
Total commitments							$ 26,500
Loan receivable commitment		$ 25,000
Loan receivable term		7 years
Variable loan receivable							25,000
Interest receivable							$ 1,900
Khoemacau | LIBOR
Acquisitions
Loans receivable variable interest rate (as a percent)		11.00%