Note 8 - Derivative Instruments - Summary of Forward Sales Contracts (Details) lb in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2025 oz lb $ / £ $ / oz	Dec. 31, 2024 lb oz $ / £ $ / oz
Silver Two Thousand Twenty Five Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	870	1,535,000
Underlying, Derivative Mass | $ / oz	35.52	31.46
Gold Two Thousand Twenty Five Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	1,000	2
Underlying, Derivative Mass | $ / oz	3,463	2,673
Zinc Two Thousand Twenty Five Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	20,889	20,834
Underlying, Derivative Mass | $ / £	1.41	1.4
Lead Two Thousand Twenty Five Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	10,637	14,661
Underlying, Derivative Mass | $ / £	0.99	0.97
Zinc 2025 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	16,976	59,194
Underlying, Derivative Mass | $ / £	1.38	1.39
Zinc 2026 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	16,755	6,283
Underlying, Derivative Mass | $ / £	1.36	1.41
Lead 2025 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	20,117	47,840
Underlying, Derivative Mass | $ / £	1	0.99
Lead 2026 Settlements For Forecasted Sale
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	52,911	52,911
Underlying, Derivative Mass | $ / £	1.03	1.03