Note 2 - Business Segments and Sales of Products - Sales of Products (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	$ 261,339	$ 189,528
Less: Smelter and refining charges	(6,712)	(13,014)
Silver Contracts [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	118,153	86,233
Gold [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	87,188	67,415
Lead [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	22,106	19,483
Zinc [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	33,125	24,964
Copper [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	391	0
Total Metal [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	254,251	185,081
Environmental Remediation Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	$ 7,088	$ 4,447