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Note 1 - Basis of Preparation of Financial Statements (Details Textual) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Jun. 30, 2021 USD ($) | Jun. 30, 2021 USD ($) | Dec. 31, 2020 USD ($) oz | Jan. 01, 2021 USD ($)
Retained Earnings (Accumulated Deficit), Ending Balance | $ (382,609) | $ (382,609) | $ (391,374) | $ 365,200
Recognition of Previously Omitted Deferred Income Taxes on Certain State Mining Income Taxes [Member] |  |  |  |
Retained Earnings (Accumulated Deficit), Ending Balance |  |  |  | $ (11,900)
Casa Berardi [Member] |  |  |  |
Decrease in Expected Gold Production Due to Suspension (Ounce) | oz |  |  | 11,700 |
Suspension Costs |  |  | $ 1,600 |
Pandemic Related Procedures Costs | $ 1,200 |  |  |
San Sebastian [Member] |  |  |  |
Suspension Costs |  |  | 1,800 |
Greens Creek [Member] |  |  |  |
Suspension Costs from Quarantining Employee Per Week |  | $ 1,000 | $ 2,300 |

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