Note 6 - Business Segments (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Number of Reportable Segments			4
Gain (Loss) on Sale of Derivatives	$ (11,226)	$ 7	$ (16,548)
Employee Labor Strike Related Costs	4,780		14,385
Lucky Friday [Member] | Suspension Costs [Member]
Employee Labor Strike Related Costs			11,100
Lucky Friday [Member] | Non-cash Depreciation Expense [Member]
Employee Labor Strike Related Costs			$ 3,300
Base Metal Derivatives [Member] | Sales [Member]
Gain (Loss) on Sale of Derivatives	$ 200