Note 6 - Business Segments (Details) - Information about Reportable Segments - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	$ 104,197	$ 117,502	$ 223,289	$ 243,289
Income (loss) from operations:
Income (loss) from operations	(17,290)	5,032	(12,368)	12,943
Identifiable assets:
Identifiable assets	2,292,268		2,292,268		$ 2,262,064
Greens Creek [Member]
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	54,043	55,449	121,398	119,045
Income (loss) from operations:
Income (loss) from operations	9,950	8,804	24,643	19,850
Identifiable assets:
Identifiable assets	715,594		715,594		704,121
Lucky Friday [Member]
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	14,570	23,762	34,460	43,858
Income (loss) from operations:
Income (loss) from operations	(585)	6,398	2,961	11,098
Identifiable assets:
Identifiable assets	376,034		376,034		356,482
Casa Berardi [Member]
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	35,584	38,291	67,431	80,386
Income (loss) from operations:
Income (loss) from operations	(3,200)	996	(3,964)	4,437
Identifiable assets:
Identifiable assets	783,296		783,296		800,961
Other Segments [Member]
Income (loss) from operations:
Income (loss) from operations	(23,455)	$ (11,166)	(36,008)	$ (22,442)
Identifiable assets:
Identifiable assets	$ 417,344		$ 417,344		$ 400,500