ASSET RETIREMENT OBLIGATIONS - Estimated Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Estimated payments of asset retirement obligations:
2023	$ 7,559
2024	4,936
2025	1,935
2026	1,569
2027	3,182
Thereafter	241,065
Aggregate undiscounted asset retirement obligations	260,246
Effect of discounting	(110,433)	$ (98,300)
Total asset retirement obligations	149,813	131,099	$ 127,898
Less: current portion	(7,559)
Asset retirement obligations	142,254	123,517
Surety bonds outstanding to performance of reclamation obligations	$ 174,300	$ 173,900