Note 6 - Business Segments - Information about Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Sales of products	$ 134,279	$ 171,302	$ 276,823	$ 302,319
Income (loss) from operations	3,975	41,610	19,846	57,183
Greens Creek [Member]
Sales of products	71,339	59,574	130,189	113,456
Income (loss) from operations	15,418	14,831	29,532	22,909
Lucky Friday [Member]
Sales of products	(187)	22,760	19,823	44,012
Income (loss) from operations	(8,212)	4,047	(4,332)	6,790
Casa Berardi [Member]
Sales of products	43,822	53,285	85,534	85,483
Income (loss) from operations	(1,708)	10,622	(3,953)	12,556
San Sebastian [Member]
Sales of products	19,305	35,683	41,277	59,368
Income (loss) from operations	11,892	25,583	25,346	40,495
Other Segments [Member]
Income (loss) from operations	$ (13,415)	$ (13,473)	$ (26,747)	$ (25,567)