Note 8 - Derivative Instruments - Summary of Forward Sales Contracts (Details) oz in Thousands, lb in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023 lb oz $ / $ $ / oz	Dec. 31, 2022 oz lb $ / $ $ / oz
Silver 2023 Settlements For Provisional Sales Member
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	931	3,124
Underlying, Derivative Mass | $ / oz	23.3	21.55
Gold 2023 Settlements For Provisional Sales Member
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz		8
Underlying, Derivative Mass | $ / oz		1,795
Zinc 2023 Settlements For Provisional Sales Member
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb		18,629
Underlying, Derivative Mass | $ / $		1.38
Lead 2023 Settlements For Provisional Sales Member
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	11,188	11,960
Underlying, Derivative Mass | $ / $	1	0.98
Silver2023 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	0
Zinc 2023 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	441	37,533
Underlying, Derivative Mass | $ / $	1.51	1.34
Lead 2023 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	7,992	75,618
Underlying, Derivative Mass | $ / $	0.99	1
Lead 2024 Settlements for Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	74,902	45,856
Underlying, Derivative Mass | $ / $	0.97	0.99
Lead 2025 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	44,754
Underlying, Derivative Mass | $ / $	0.97