Note 11 - Business Segments and Significant Customers - Information about Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net sales to unaffiliated customers	$ 645,957	$ 443,567	$ 500,781
Income (loss) from operations	116,944	(35,611)	21,628
Capital additions (including non-cash additions)	181,799	160,716	151,085
Depreciation, depletion and amortization	115,468	111,489	111,134
Other significant non-cash items	15,850	71,204	4,232
Identifiable assets	2,371,677	2,221,925	2,262,064
Greens Creek [Member]
Net sales to unaffiliated customers	260,446	227,833	245,175
Income (loss) from operations	65,125	26,536	39,758
Capital additions (including non-cash additions)	42,013	45,962	31,476
Depreciation, depletion and amortization	52,564	56,553	63,505
Other significant non-cash items	2,736	2,886	2,807
Identifiable assets	681,303	698,265	704,121
Lucky Friday [Member]
Net sales to unaffiliated customers	94,479	66,302	89,757
Income (loss) from operations	18,175	868	21,501
Capital additions (including non-cash additions)	44,839	60,020	52,193
Depreciation, depletion and amortization	11,810	11,262	9,431
Other significant non-cash items	720	72	72
Identifiable assets	442,829	393,338	356,482
Casa Berardi [Member]
Net sales to unaffiliated customers	177,143	149,432	165,849
Income (loss) from operations	16,336	(1,557)	11,828
Capital additions (including non-cash additions)	67,577	35,302	48,615
Depreciation, depletion and amortization	47,312	43,674	38,198
Other significant non-cash items	1,259	2,229	847
Identifiable assets	806,044	779,423	800,961
San Sebastian [Member]
Net sales to unaffiliated customers	113,889
Income (loss) from operations	77,221	(9,269)	(5,780)
Capital additions (including non-cash additions)	6,026	4,623
Depreciation, depletion and amortization	3,782
Other significant non-cash items		13
Identifiable assets	33,608	22,238	1,529
Other Segments [Member]
Income (loss) from operations	(59,913)	(52,189)	(45,679)
Capital additions (including non-cash additions)	21,344	14,809	18,801
Other significant non-cash items	11,135	66,004	506
Identifiable assets	$ 407,893	$ 328,661	$ 398,971