Note 11 - Business Segments and Significant Customers (Details) - Information about Reportable Segments (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	$ 500,781us-gaap_Revenues	$ 382,589us-gaap_Revenues	$ 321,143us-gaap_Revenues
Income (loss) from operations	21,628	(32,394)	37,866
Capital additions	151,085	162,608	129,942
Depreciation, depletion and amortization	112,173	82,366	50,113
Other significant non-cash items	4,232us-gaap_OtherNoncashIncomeExpense	4,043us-gaap_OtherNoncashIncomeExpense	38,051us-gaap_OtherNoncashIncomeExpense
Identifiable assets	2,262,064us-gaap_Assets	2,232,119us-gaap_Assets	1,378,290us-gaap_Assets
Greens Creek [Member]
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	245,175	263,263	320,895
Income (loss) from operations	39,758	62,178	138,245
Capital additions	31,476	57,119	62,184
Depreciation, depletion and amortization	63,505	55,265	43,522
Other significant non-cash items	2,807	1,961	4,037
Identifiable assets	704,121	744,027	741,666
Lucky Friday [Member]
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	89,757	44,204	248
Income (loss) from operations	21,502	(3,563)	(25,179)
Capital additions	52,193	55,902	55,998
Depreciation, depletion and amortization	9,431	7,833
Other significant non-cash items	72	96	92
Identifiable assets	356,482	313,793	226,196
Casa Berardi [Member]
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	165,849	75,122
Income (loss) from operations	11,828	(15,708)
Capital additions	48,615	41,425
Depreciation, depletion and amortization	38,198	18,030
Other significant non-cash items	847	474
Identifiable assets	800,961	821,058
Other Segments [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(51,460)	(75,301)	(75,200)
Capital additions	18,801	8,162	11,760
Other significant non-cash items	506	1,512	33,922
Identifiable assets	400,500	353,241	410,428
Segment Depreciation Depletion and Amortization [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	$ 111,134	$ 81,128	$ 43,522

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 7

Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-Name Regulation S-X (SX)

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-Section 02

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- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-Topic 810

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 225

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-Subparagraph (SX 210.5-03.13)

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Other income (expense) included in net income that results in no cash inflows or outflows in the period. Includes noncash adjustments to reconcile net income (loss) to cash provided by (used in) operating activities that are not separately disclosed.

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Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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