Note 6 - Business Segments and Sales of Products - Information About Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Net sales		$ 152,617	$ 139,709
Income (loss) from operations		(16,124)	11,949
Identifiable assets		2,694,605		$ 2,703,944
Greens Creek [Member]
Net sales		80,129	65,850
Income (loss) from operations		25,433	23,152
Identifiable assets		640,241		637,386
Lucky Friday [Member]
Net sales		2,182	4,977
Income (loss) from operations		(2,781)	(4,146)
Identifiable assets		440,433		437,499
Casa Berardi [Member]
Net sales		40,062	55,548
Income (loss) from operations	[1]	(10,519)	3,250
Identifiable assets		739,978		754,248
San Sebastian [Member]
Net sales		12,600	13,334
Income (loss) from operations		(1,512)	5,017
Identifiable assets		54,152		44,152
Nevada Operations [Member]
Net sales		17,644
Income (loss) from operations		(13,991)
Identifiable assets		575,197		581,194
Other Segments [Member]
Income (loss) from operations		(12,754)	$ (15,324)
Identifiable assets		$ 244,604		$ 249,465

[1] Amounts reported as of and for the years ended December 31, 2017 and 2016 have been revised. See Note 2 for more information.