UNAUDITED SUPPLEMENTARY QUARTERLY INFORMATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
UNAUDITED SUPPLEMENTARY QUARTERLY INFORMATION
Revenue from gold and silver sales	$ 58,680	$ 38,404	$ 34,395	$ 34,752	$ 28,240	$ 25,988	$ 30,647	$ 25,542	$ 166,231	$ 110,417	$ 136,541
Gross profit (loss)	13,050	3,755	(3,468)	4,443	(288)	1,503	4,235	(5,994)	17,780	(544)	(6,480)
Net income (loss)	$ 138,453	$ (18,451)	$ (21,627)	$ (43,076)	$ (37,364)	$ (9,976)	$ (14,409)	$ (19,326)	$ 55,299	$ (81,075)	$ (56,712)
Net (loss) per share:
Basic (in dollars per share)	$ 2.89	$ (0.39)	$ (0.46)	$ (0.91)	$ (0.79)	$ (0.21)	$ (0.30)	$ (0.41)	$ 1.16	$ (1.71)	$ (1.25)
Diluted (in dollars per share)	$ 2.89	$ (0.39)	$ (0.46)	$ (0.91)	$ (0.79)	$ (0.21)	$ (0.30)	$ (0.41)	$ 1.16	$ (1.71)	$ (1.25)
Weighted average shares outstanding:
Basic (in shares)	47,844	47,471	47,428	47,428	47,428	47,427	47,428	47,369	47,544	47,427	45,490
Diluted (in shares)	47,844	47,471	47,428	47,428	47,428	47,427	47,428	47,369	47,544	47,427	45,490