COMMITMENTS AND CONTINGENCIES - Prepayment Agreement (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Other Commitments [Line Items]
Revenue	$ 25,988,000	$ 37,129,000	$ 82,177,000	$ 101,575,000
Remaining net proceeds recorded as deferred revenue	4,715,000		4,715,000
Gold and silver sales
Other Commitments [Line Items]
Revenue	10,208,000	$ 37,129,000	66,397,000	$ 101,575,000
Prepayment Agreement | Auramet International LLC guarantee obligation
Other Commitments [Line Items]
Remaining net proceeds recorded as deferred revenue	$ 4,700,000		$ 4,700,000
Number of ounces of gold pledged but not delivered	2,860		2,860
Prepayment Agreement | Auramet International LLC guarantee obligation | Auramet Revolving Facility [Member]
Other Commitments [Line Items]
Net proceeds from Auramet Facility	$ 20,500,000		$ 20,500,000
Prepayment Agreement | Auramet International LLC guarantee obligation | Gold and silver sales
Other Commitments [Line Items]
Revenue	$ 15,800,000		$ 15,800,000