Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Sales	$ 929,925	$ 720,227	$ 718,905
Cost of sales and other direct production costs	548,245	458,504	458,811
Depreciation, depletion and amortization	183,470	148,774	143,938
Total cost of sales	731,715	607,278	602,749
Gross profit	198,210	112,949	116,156
Other operating expenses:
General and administrative	45,405	42,722	43,384
Exploration and pre-development	27,321	32,512	46,041
Ramp-up and suspension costs	43,307	76,252	24,114
Provision for closed operations and environmental matters	6,843	7,575	8,793
Writedown of property, plant and equipment	14,574	0	0
Other operating (income) expense, net	(45,516)	(1,438)	6,262
Total other operating expenses	91,934	157,623	128,594
Income (loss) from operations	106,276	(44,674)	(12,438)
Other expense:
Fair value adjustments, net	(2,204)	2,925	(4,723)
Foreign exchange gain (loss), net	7,552	(3,810)	7,211
Other income	4,426	5,883	7,829
Interest expense	(49,834)	(43,319)	(42,793)
Total other expense:	(40,060)	(38,321)	(32,476)
Income (loss) before income and mining taxes	66,216	(82,995)	(44,914)
Income and mining tax (provision) benefit	(30,414)	(1,222)	7,566
Net income (loss)	35,802	(84,217)	(37,348)
Preferred stock dividends	(552)	(552)	(552)
Net income (loss) applicable to common stockholders	35,250	(84,769)	(37,900)
Comprehensive income (loss):
Net Income (Loss)	35,802	(84,217)	(37,348)
Unrealized (loss) gain and amortization of prior service on pension plans	(8,389)	(1,157)	17,067
Unrealized (loss) gain on derivative contracts designated as hedge transactions	(7,714)	4,546	13,837
Total change in accumulated other comprehensive (loss) income, net	(16,103)	3,389	30,904
Comprehensive income (loss)	$ 19,699	$ (80,828)	$ (6,444)
Basic income (loss) common share after preferred dividends	$ 0.06	$ (0.14)	$ (0.07)
Diluted income (loss) per common share after preferred dividends	$ 0.06	$ (0.14)	$ (0.07)
Weighted average number of common shares outstanding - basic	620,848	605,668	557,344
Weighted average number of common shares outstanding - diluted	622,535	605,668	557,344