Note 6 - Business Segments and Sales of Products - Information About Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Net sales		$ 134,172	$ 147,259	$ 286,789	$ 286,968
Income (loss) from operations		(43,477)	3,756	(59,601)	15,705
Identifiable assets		2,670,713		2,670,713		$ 2,703,944
Greens Creek [Member]
Net sales		55,398	74,605	135,527	140,455
Income (loss) from operations		9,141	25,516	34,574	48,668
Identifiable assets		643,811		643,811		637,386
Lucky Friday [Member]
Net sales		4,951	3,287	7,133	8,264
Income (loss) from operations		(2,271)	(5,261)	(5,052)	(9,407)
Identifiable assets		438,362		438,362		437,499
Casa Berardi [Member]
Net sales		45,500	56,103	85,562	111,651
Income (loss) from operations	[1]	(15,363)	1,014	(25,882)	4,264
Identifiable assets		722,882		722,882		754,248
San Sebastian [Member]
Net sales		10,993	13,264	23,593	26,598
Income (loss) from operations		(1,923)	(361)	(3,435)	4,656
Identifiable assets		53,606		53,606		44,152
Nevada Operations [Member]
Net sales		17,330	0	34,974	0
Income (loss) from operations		(21,475)	0	(35,466)	0
Identifiable assets		571,177		571,177		581,194
Other Segments [Member]
Income (loss) from operations		(11,586)	$ (17,152)	(24,340)	$ (32,476)
Identifiable assets		$ 240,875		$ 240,875		$ 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.