Note 2 - Business Segments and Sales of Products - Sales of Products (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	$ 409,542	$ 245,085	$ 974,908	$ 680,270
Less: Smelter and refining charges	(3,397)	(10,519)	(12,653)	(32,815)
Silver Contracts [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	190,050	109,756	430,864	308,681
Gold [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	144,017	79,239	354,926	229,123
Lead [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	24,379	21,591	67,961	65,002
Zinc [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	37,422	37,281	101,685	94,741
Copper [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	880	409	2,250	409
Total Metal [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	393,351	237,757	945,033	665,141
Environmental Remediation Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	$ 16,191	$ 7,328	$ 29,875	$ 15,129