Note 8 - Derivative Instruments - Summary of Forward Sales Contracts (Details) lb in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024 lb oz $ / £ $ / oz	Dec. 31, 2023 lb oz $ / £ $ / oz
Silver 2024 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	1,460,000
Underlying, Derivative Mass | $ / oz	30.29
Gold 2024 Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	500
Underlying, Derivative Mass | $ / oz	2,689
Silver 2023 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz		735,000
Underlying, Derivative Mass | $ / oz		24.4
Gold 2023 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz		3
Underlying, Derivative Mass | $ / oz		2,045
Zinc 2023 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb		441
Underlying, Derivative Mass | $ / £		1.51
Zinc 2024 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	18,905
Underlying, Derivative Mass | $ / £	1.36
Zinc 2024 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	4,299
Underlying, Derivative Mass | $ / £	1.31
Zinc 2025 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	26,455
Underlying, Derivative Mass | $ / £	1.39
Lead 2023 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb		15,542
Underlying, Derivative Mass | $ / £		1
Lead 2024 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	13,558
Underlying, Derivative Mass | $ / £	0.97
Lead 2024 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	4,519	56,713
Underlying, Derivative Mass | $ / £	0.97	0.98
Lead 2025 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	62,501	49,273
Underlying, Derivative Mass | $ / £	0.98	0.98
Lead 2026 Settlements For Forecasted Sale
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	33,290
Underlying, Derivative Mass | $ / £	1.04