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Note 4 - Properties, Plants, Equipment and Mineral Interests, and Lease Commitments (Details Textual) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Payments to Acquire Property, Plant, and Equipment, Total | $ 91,016 | $ 121,421 | $ 136,933
Suspension Related Costs | 13,500 |  |
Assets on Care and Maintenance, Depreciation Expense | 5,600 |  |
Costs for Mining Material | 7,700 |  |
Costs Related to Mining Non-refractory Ore | 11,500 |  |
Property, Plant and Equipment, Net, Ending Balance | 2,345,219 | 2,423,698 |
Capital Leased Assets, Gross, Total | 74,000 | 64,900 |
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation | 51,700 | $ 44,300 |
Mineral Interests [Member] | NEVADA |  |  |
Property, Plant and Equipment, Net, Ending Balance | 474,300 |  |
Lucky Friday [Member] |  |  |
Payments to Acquire Property, Plant, and Equipment, Total | 25,700 |  |
Greens Creek [Member] |  |  |
Payments to Acquire Property, Plant, and Equipment, Total | 19,700 |  |
Mining Assets, Value Beyond Proven and Probable Reserves (VBPP) | 132,600 |  |
Casa Berardi [Member] |  |  |
Payments to Acquire Property, Plant, and Equipment, Total | 40,900 |  |
Mining Assets, Value Beyond Proven and Probable Reserves (VBPP) | 321,100 |  |
San Sebastian [Member] |  |  |
Payments to Acquire Property, Plant, and Equipment, Total | 500 |  |
Nevada Operations [Member] |  |  |
Payments to Acquire Property, Plant, and Equipment, Total | 4,000 |  |
Mining Assets, Value Beyond Proven and Probable Reserves (VBPP) | $ 382,200 |  |

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- Definition Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121569800&loc=d3e45014-112735 + Details
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