Note 2 - Business Segments and Sales of Products - Sales of Products (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Segment Reporting [Line Items]
Total sales	$ 394,820	$ 315,998	$ 1,140,104	$ 740,324
Less: Smelter and refining charges	1,826	(3,397)	662	(12,653)
Silver [Member]
Segment Reporting [Line Items]
Total sales	257,697	189,775	767,058	430,227
Gold [Member]
Segment Reporting [Line Items]
Total sales	54,368	50,748	154,550	120,979
Lead [Member]
Segment Reporting [Line Items]
Total sales	23,991	24,379	70,652	67,961
Zinc [Member]
Segment Reporting [Line Items]
Total sales	33,892	37,422	108,235	101,685
Copper [Member]
Segment Reporting [Line Items]
Total sales	680	880	1,100	2,250
Total metal sales [Member]
Segment Reporting [Line Items]
Total sales	372,454	299,807	1,102,257	710,449
Environmental Remediation Services [Member]
Segment Reporting [Line Items]
Total sales	$ 22,366	$ 16,191	$ 37,847	$ 29,875

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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