Note 6 - Business Segments and Sales of Products - Information About Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Net sales	$ 136,925	$ 152,617
Income (loss) from operations	(14,960)	(16,124)
Greens Creek	2,764,124		$ 2,637,308
Greens Creek [Member]
Net sales	53,833	80,129
Income (loss) from operations	4,117	25,433
Greens Creek	631,246		639,047
Lucky Friday [Member]
Net sales	2,830	2,182
Income (loss) from operations	(8,120)	(2,781)
Greens Creek	488,854		440,615
Casa Berardi [Member]
Net sales	46,172	40,062
Income (loss) from operations	(3,880)	(10,519)
Greens Creek	698,433		703,511
San Sebastian [Member]
Net sales	9,927	12,600
Income (loss) from operations	679	(1,512)
Greens Creek	35,254		48,294
Nevada Operations [Member]
Net sales	24,163	17,644
Income (loss) from operations	2,889	(13,991)
Greens Creek	522,899		528,466
Other Segments [Member]
Income (loss) from operations	(10,645)	$ (12,754)
Greens Creek	$ 387,438		$ 277,375