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Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 USD ($) oz | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Jan. 01, 2019 USD ($)
Restricted Cash and Cash Equivalents, Noncurrent, Total | $ 1,053 | $ 1,025 |  |
Capitalized Drilling Costs | 4,400 | 14,400 | $ 11,600 |
Operating Lease, Liability, Total | 10,642 |  |  |
Foreign Currency Transaction Gain (Loss), Realized | (4,605) | (8,236) | $ 10,310 |
Operating Lease, Right-of-Use Asset | $ 10,628 | $ 16,381 |  |
Accounting Standards Update 2016-02 [Member] |  |  |  |
Operating Lease, Liability, Total |  |  |  | $ 22,400
Minimum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) | 3 years |  |  |
Maximum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) | 17 years |  |  |
Casa Berardi [Member] |  |  |  |
Decrease in Expected Gold Production Due to Suspension (Ounce) | oz | 11,700 |  |  |
Suspension Costs | $ 1,600 |  |  |
San Sebastian [Member] |  |  |  |
Suspension Costs | 1,800 |  |  |
Greens Creek [Member] |  |  |  |
Suspension Costs from Quarantining Employee Per Week | $ 2,300 |  |  |

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