Note 8 - Derivative Instruments - Summary of Forward Sales Contracts (Details) lb in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024 oz lb $ / £ $ / oz	Dec. 31, 2023 lb oz $ / oz $ / £
Silver 2024 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	2,250,000
Underlying, Derivative Mass | $ / oz	29.83
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	8,488
Underlying, Derivative Mass | $ / £	1.29
Zinc 2024 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	13,173
Underlying, Derivative Mass | $ / £	1.34
Zinc 2025 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	9,700
Underlying, Derivative Mass | $ / £	1.4
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	15,322
Underlying, Derivative Mass | $ / £	0.99
Lead 2024 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	19,842	56,713
Underlying, Derivative Mass | $ / £	0.96	0.98
Lead 2025 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	63,824	49,273
Underlying, Derivative Mass | $ / £	0.98	0.98