Note 6 - Business Segments (Details) - Information about Reportable Segments (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	$ 119,092	$ 125,787
Income (loss) from operations:
Income (loss) from operations	4,922	7,911
Identifiable assets:
Identifiable assets	2,259,951	2,262,064	2,262,064
Greens Creek [Member]
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	67,355	63,596
Income (loss) from operations:
Income (loss) from operations	14,693	11,046
Identifiable assets:
Identifiable assets	704,348	704,121
Lucky Friday [Member]
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	19,891	20,096
Income (loss) from operations:
Income (loss) from operations	3,546	4,700
Identifiable assets:
Identifiable assets	369,503	356,482
Casa Berardi [Member]
Net sales to unaffiliated customers:
Net sales to unaffiliated customers	31,846	42,095
Income (loss) from operations:
Income (loss) from operations	(765)	3,441
Identifiable assets:
Identifiable assets	789,989	800,961
Other Segments [Member]
Income (loss) from operations:
Income (loss) from operations	(12,552)	(11,276)
Identifiable assets:
Identifiable assets	$ 396,111	$ 400,500