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Note 11 - Commitments, Contingencies and Obligations (Details Textual) - USD ($) $ in Thousands |  |  | 1 Months Ended | 3 Months Ended
--- | --- | --- | --- | ---
Dec. 14, 2023 | Jul. 12, 2022 | Jul. 31, 2018 | Aug. 31, 2012 | Jun. 30, 2011 | Mar. 31, 2024 | Mar. 31, 2023
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Environmental remediation expense |  |  |  |  |  | $ 986 | $ 1,044
Finance lease, liability, to be paid |  |  |  |  |  | 26,389 |
Lessee, operating lease, liability, to be paid |  |  |  |  |  | 13,475 |
Lease Commitments [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Lessee, operating lease, liability, to be paid |  |  |  |  |  | 13,500 |
Performance Obligation Commitments [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Surety Bonds |  |  |  |  |  | 195,300 |
Letters of credit outstanding, amount |  |  |  |  |  | 6,800 |
Greens Creek [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual obligation |  |  |  |  |  | 26,400 |
Greens Creek [Member] | Purchase Orders and Commitment [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual obligation |  |  |  |  |  | 11,100 |
Lucky Friday [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
EPA maximum for statutory penalties, per day/violation |  | $ 59,973 |  |  |  |  |
EPA maximum for administrative penalties, per day/violation |  | 23,989 |  |  |  |  |
EPA maximum for administrative penalties |  | $ 299,989 |  |  |  |  |
Lucky Friday [Member] | Purchase Orders and Commitment [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual obligation |  |  |  |  |  | 17,500 |
Keno Hill [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Maximum Offense Fine | $ 100,000 |  |  |  |  |  |
Keno Hill [Member] | Purchase Orders and Commitment [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual obligation |  |  |  |  |  | 10,200 |
Casa Berardi [Member] | Purchase Orders and Commitment [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual obligation |  |  |  |  |  | 2,500 |
Nevada Operations [Member] | Purchase Orders and Commitment [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual obligation |  |  |  |  |  | 800 |
Johnny M Mine Area near San Mateo, New Mexico [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Payment of response costs |  |  |  | $ 1,100 |  |  |
Estimated response costs |  |  | $ 9,600 |  |  |  |
Environmental remediation expense |  |  |  | 10,100 |  |  |
Johnny M Mine Area near San Mateo, New Mexico [Member] | Environmental Remediation Past Response Costs [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Accrual for environmental loss contingencies, period increase (decrease) |  |  |  | $ 10,100 |  | $ 10,100 |
Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member] |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Estimated response costs |  |  |  |  | $ 4,500 |  |
Estimated future response cost |  |  |  |  | $ 100,000 |  |

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- Definition Represents the amount of surety bonds in place as of a specified date. Such surety bonds may be for the purpose of, but not limited to, financial support for future reclamation and closure costs, self-insurance, and employee benefit plans. + References No definition available. + Details
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