Note 2 - Business Segments and Sales of Products - Sales of Products (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	$ 333,851	$ 218,992	$ 745,284	$ 424,326
Less: Smelter and refining charges	4,247	(2,544)	(1,164)	(9,256)
Silver [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	213,728	122,475	509,361	240,452
Gold [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	43,205	38,872	100,182	70,231
Lead [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	24,364	21,476	46,661	43,582
Zinc [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	37,470	31,138	74,343	64,263
Copper [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	8	979	420	1,370
Total metal sales [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	323,022	212,396	729,803	410,642
Environmental Remediation Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total sales	$ 10,829	$ 6,596	$ 15,481	$ 13,684