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