Note 6 - Business Segments - Information about Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Sales of products	$ 142,544	$ 131,017
Income from operations	15,871	15,573
Greens Creek [Member]
Sales of products	58,850	53,882
Income from operations	14,114	8,078
Lucky Friday [Member]
Sales of products	20,010	21,252
Income from operations	3,880	2,743
Casa Berardi [Member]
Sales of products	41,712	32,198
Income from operations	(2,245)	1,934
San Sebastian [Member]
Sales of products	21,972	23,685
Income from operations	13,454	14,912
Other Segments [Member]
Income from operations	$ (13,332)	$ (12,094)