Note 8 - Derivative Instruments - Summary of Forward Sales Contracts (Details) oz in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2026 USD ($) oz lb $ / £	Dec. 31, 2025 lb $ / £
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| oz	3,292
Assets Needed for Immediate Settlement, Aggregate Fair Value \| $	$ 50
Silver 2026 Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| oz	295,000
Silver 2026 Settlements For Provisional Sales [Member] \| Maximum [Member]
Derivative [Line Items]
Assets Needed for Immediate Settlement, Aggregate Fair Value \| $	$ 61,670
Silver 2026 Settlements For Provisional Sales [Member] \| Minimum [Member]
Derivative [Line Items]
Assets Needed for Immediate Settlement, Aggregate Fair Value \| $	$ 72,700
Gold 2026 Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| oz	120
Zinc 2026 Settlements for Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass	20,448	18,850
Underlying, Derivative Mass \| $ / £	1.36	1.37
Zinc 2028 Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass	2,425
Underlying, Derivative Mass \| $ / £	1.36
Lead 2026 Settlements For Provisional Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass	6,504	13,117
Underlying, Derivative Mass \| $ / £	0.97	1.05
Zinc 2026 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass		53,407
Underlying, Derivative Mass \| $ / £		1.33
Zinc 2027 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass	50,816	23,810
Underlying, Derivative Mass \| $ / £	1.42	1.36
Zinc 2028 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass	44,974
Underlying, Derivative Mass \| $ / £	1.54
Lead 2026 Settlements For Forecasted Sale [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass	2,315	42,108
Underlying, Derivative Mass \| $ / £	0.99	1.02
Lead 2027 Settlements For Forecasted Sales [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Mass		0
Gold 2026 Settlements For Forecasted Sales [Member] \| Maximum [Member]
Derivative [Line Items]
Assets Needed for Immediate Settlement, Aggregate Fair Value \| $	$ 4,600,000
Gold 2026 Settlements For Forecasted Sales [Member] \| Minimum [Member]
Derivative [Line Items]
Assets Needed for Immediate Settlement, Aggregate Fair Value \| $	$ 4,200,000

The aggregate fair value of assets needed to immediately settle the derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4H
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4H

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-5A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-5

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+ References

No definition available.

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