Note 11 - Business Segments and Significant Customers (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	Year Ended December 31,
	2017			2016			2015
Greens Creek		48.2	%		40.3	%		51.4	%
Lucky Friday		3.8	%		14.7	%		14.9	%
Casa Berardi		33.3	%		27.4	%		33.7	%
San Sebastian		14.8	%		17.6	%		—	%
		100	%		100	%		100	%

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	2017			2016			2015
Net sales to unaffiliated customers:
Greens Creek	$	278,297		$	260,446		$	227,833
Lucky Friday		21,555			94,479			66,302
Casa Berardi		192,165			177,143			149,432
San Sebastian		85,758			113,889			—
	$	577,775		$	645,957		$	443,567
Income (loss) from operations:
Greens Creek	$	70,132		$	65,125		$	26,536
Lucky Friday		(16,037	)		18,175			868
Casa Berardi		4,003			16,336			(1,557	)
San Sebastian		53,591			77,221			(9,269	)
Other		(47,046	)		(59,913	)		(52,189	)
	$	64,643		$	116,944		$	(35,611	)
Capital additions (including non-cash additions):
Greens Creek	$	35,255		$	42,013		$	45,962
Lucky Friday		6,268			44,839			60,020
Casa Berardi		51,327			67,577			35,302
San Sebastian		9,994			6,026			4,623
Other		2,908			21,344			14,809
	$	105,752		$	181,799		$	160,716
Depreciation, depletion and amortization:
Greens Creek	$	56,328		$	53,222		$	57,742
Lucky Friday		2,447			11,810			11,262
Casa Berardi		54,594			47,312			43,674
San Sebastian		2,693			3,782			—
	$	116,062		$	116,126		$	112,678
Other significant non-cash items:
Greens Creek	$	2,685		$	2,736		$	2,886
Lucky Friday		2,011			720			72
Casa Berardi		653			1,259			2,229
San Sebastian		468			—			13
Other		51,182			11,135			66,004
	$	56,999		$	15,850		$	71,204
Identifiable assets:
Greens Creek	$	671,960		$	681,303		$	698,265
Lucky Friday		432,400			442,829			393,338
Casa Berardi		804,505			806,044			779,423
San Sebastian		62,198			33,608			22,238
Other		393,894			407,893			328,661
	$	2,364,957		$	2,371,677		$	2,221,925

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

	2017		2016		2015
United States	$	16,776	$	22,499	$	17,862
Canada		358,663		437,621		275,771
Japan		58,475		44,158		38,835
Korea		80,183		116,687		66,293
China		69,631		35,220		38,611
Other		—		4,008		—
Total, excluding gains/losses on forward contracts	$	583,728	$	660,193	$	437,372

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]

	2017		2016
United States	$	1,246,577	$	1,261,488
Canada		759,700		764,489
Mexico		13,744		6,708
	$	2,020,021	$	2,032,685

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

	Year Ended December 31,
	2017			2016			2015
Teck Metals Ltd.		11.3	%		21.2	%		22.5	%
Korea Zinc		16.4	%		16.9	%		16.0	%
Scotia		24.9	%		24.5	%		5.6	%
CIBC		22.8	%		19.0	%		17.6	%
Mitsui		7.6	%		4.4	%		10.2	%