INCOME AND MINING TAXES - Tax Effects of Temporary Differences (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryforward	$ 61,135	$ 57,983
Mineral properties	52,228	52,471
Other temporary differences	22,259	21,857
Total gross deferred tax assets	135,622	132,311
Less: valuation allowance	(132,396)	(130,002)	$ (149,342)	$ (149,921)
Net deferred tax assets	3,226	2,309
Deferred tax liabilities:
Acquired mineral property interests	(3,928)	(2,895)
Other taxable temporary differences	(35,928)	(39,986)
Total deferred tax liabilities	(39,856)	(42,881)
Deferred income and mining tax liability	$ (36,630)	$ (40,572)