Note 12 - Business Segments and Sales of Products - Information About Reportable Segments (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net sales		$ 567,137	$ 577,775	$ 645,957
Income (loss) from operations	[1]	(39,126)	60,106	109,439
Capital additions (including non-cash additions)		146,451	105,752	181,799
Depreciation, depletion and amortization	[1]	134,044	120,599	123,631
Other significant non-cash items	[1]	(9,542)	57,463	16,323
Identifiable assets	[1]	2,703,944	2,345,158	2,355,795
Greens Creek [Member]
Net sales		265,650	278,297	260,446
Income (loss) from operations		70,293	70,132	65,125
Capital additions (including non-cash additions)		43,631	35,255	42,013
Depreciation, depletion and amortization		46,511	56,328	53,222
Other significant non-cash items		3,325	2,685	2,736
Identifiable assets		637,386	671,960	681,303
Lucky Friday [Member]
Net sales		9,750	21,555	94,479
Income (loss) from operations		(20,199)	(16,037)	18,175
Capital additions (including non-cash additions)		14,236	6,268	44,839
Depreciation, depletion and amortization		1,012	2,447	11,810
Other significant non-cash items		618	2,011	720
Identifiable assets		437,499	432,400	442,829
Casa Berardi [Member]
Net sales		210,339	192,165	177,143
Income (loss) from operations	[1]	881	(534)	8,831
Capital additions (including non-cash additions)		39,816	51,327	67,577
Depreciation, depletion and amortization	[1]	71,302	59,131	54,817
Other significant non-cash items	[1]	696	33	1,072
Identifiable assets	[1]	754,248	784,706	790,162
San Sebastian [Member]
Net sales		50,224	85,758	113,889
Income (loss) from operations		(14)	53,591	77,221
Capital additions (including non-cash additions)		8,492	9,994	6,026
Depreciation, depletion and amortization		4,602	2,693	3,782
Other significant non-cash items		419	468
Identifiable assets		44,152	62,198	33,608
Nevada Operations [Member]
Net sales		31,174
Income (loss) from operations		(26,715)
Capital additions (including non-cash additions)		35,721
Depreciation, depletion and amortization		10,617
Other significant non-cash items		8,758
Identifiable assets		581,194
Other Segments [Member]
Income (loss) from operations		(63,372)	(47,046)	(59,913)
Capital additions (including non-cash additions)		4,555	2,908	21,344
Other significant non-cash items		(23,358)	52,266	11,795
Identifiable assets		$ 249,465	$ 393,894	$ 407,893

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