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Note 16 - Acquisitions (Details Textual) $ / shares in Units, $ / shares in Units, $ in Thousands, $ in Millions |  |  |  |  | 1 Months Ended | 12 Months Ended | 34 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Jul. 20, 2018 USD ($) $ / shares shares | Jul. 19, 2018 shares | Sep. 13, 2016 USD ($) $ / shares shares | Jun. 27, 2016 CAD ($) $ / shares shares | Sep. 30, 2016 USD ($) shares | Jun. 30, 2015 USD ($) $ / shares shares | Dec. 31, 2018 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2016 USD ($) shares | Dec. 31, 2018 USD ($) shares
Common Stock, Shares, Issued, Total | shares |  |  |  |  |  |  | 482,603,937 | 399,176,425 |  | 482,603,937
Stock Issued During Period, Shares, New Issues | shares |  |  |  |  |  |  | 2,564,767 |  |  | 7,173,614
Class of Warrant or Right, Outstanding | shares |  |  |  |  |  |  | 0 | 0 | 0 | 0
Business Combination, Acquisition Related Costs |  |  |  |  |  |  | $ 10,045 | $ 25 | $ 2,695 |
Common Stock, Shares, Outstanding, Ending Balance | shares |  |  |  |  |  |  | 482,603,937 | 399,176,425 |  | 482,603,937
Warrants in Connection with Klondex Mines Acquisition [Member] |  |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Issued During Period | shares | 4,136,000 |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares | 1 |  |  |  |  |  |  |  |  |
Warrants in Connection with Klondex Mines Acquisition Expiring April 2032 [Member] |  |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Outstanding | shares | 2,068,000 |  |  |  |  |  |  |  |  |
Warrants in Connection with Klondex Mines Acquisition Expiring February 2029 [Member] |  |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Outstanding | shares | 2,068,000 |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares | $ 1.57 |  |  |  |  |  |  |  |  |
Klondex Mines Ltd [Member] |  |  |  |  |  |  |  |  |  |
Common Stock, Shares, Issued, Total | shares | 182,048,945 | 180,499,319 |  |  |  |  |  |  |  |
Stock Issued During Period, Shares, New Issues | shares |  | 1,549,626 |  |  |  |  |  |  |  |
Common Stock, Shares, Outstanding, Ending Balance | shares | 182,048,945 | 180,499,319 |  |  |  |  |  |  |  |
Klondex Mines Ltd [Member] |  |  |  |  |  |  |  |  |  |
Business Acquisition, Share Price | $ / shares | $ 2.24 |  |  |  |  |  |  |  |  |
Business Acquisition, Percentage of Voting Interests Acquired | 100.00% |  |  |  |  |  |  |  |  |
Business Combination, Consideration, Cash Alternative, Price Per Share | $ / shares | $ 2.47 |  |  |  |  |  |  |  |  |
Business Combination, Consideration, Share Alternative, Share Exchange Rate | 0.6272 |  |  |  |  |  |  |  |  |
Business Combination Consideration, Combined Alternative, Price Per Share | $ / shares | $ 0.8411 |  |  |  |  |  |  |  |  |
Business Combination Consideration, Combined Alternative, Share Exchange Rate | 0.4136 |  |  |  |  |  |  |  |  |
Payments to Acquire Businesses, Gross | $ 161,704 |  |  |  |  |  |  |  |  |
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares | 75,276,176 |  |  |  |  |  |  |  |  |
Stock Issued During Period, Shares, New Issues | shares | 75,276,176 |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares | $ 8.02 |  |  |  |  |  |  |  |  |
Employee Service Share-based Compensation, Cash Flow Effect, Cash Used to Settle Awards | $ 2,000 |  |  |  |  |  |  |  |  |
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable | 242,389 |  |  |  |  |  |  |  |  |
Business Combination, Consideration Transferred, Total | 414,248 |  |  |  |  |  |  |  |  |
Business Combination, Subscrition of New Formed Company, Value | 7,000 |  |  |  |  |  |  |  |  |
Business Combination, Settlement of Certain Equity Compensation Value | 1,500 |  |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total | 521,495 |  |  |  |  |  | $ 19,200 |  |  | $ 19,200
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual |  |  |  |  |  |  | 31,200 |  |  |
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |  |  |  |  |  |  | $ 26,700 |  |  |
Klondex Mines Ltd [Member] | Hecla Warrants [Member] |  |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Issued During Period, Value | 10,200 |  |  |  |  |  |  |  |  |
Klondex Mines Ltd [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |
Payments to Acquire Businesses, Gross | $ 153,200 |  |  |  |  |  |  |  |  |
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares | 75,276,176 |  |  |  |  |  |  |  |  |
Revett Mining Company, Inc. [Member] |  |  |  |  |  |  |  |  |  |
Business Acquisition, Share Price | $ / shares |  |  | $ 5.79 |  |  |  |  |  |  |
Payments to Acquire Businesses, Gross |  |  | $ 4,025 |  |  | $ 4,000 |  |  |  |
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares |  |  | 8,309,006 |  |  | 8,309,006 |  |  |  |
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable |  |  | $ 48,109 |  |  | $ 48,100 |  |  |  |
Business Combination, Consideration Transferred, Total |  |  | 52,134 |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total |  |  | $ 74,320 |  |  | $ 74,300 |  |  |  |
Ownership Percentage |  |  | 100.00% |  |  |  |  |  |  |
Business Acquistion, Number of Common Stock Shares Exchanged for Each Share of Acquiree Common Stock | shares |  |  |  |  |  | 0.2218 |  |  |  |
Business Acquisition, Common Shares Outstanding of Acquiree | shares |  |  |  |  |  | 36,498,625 |  |  |  |
Business Acquisition, Shares Owned by Subsidary, Number of Shares Cancelled | shares |  |  |  |  |  | 963,079 |  |  |  |
Business Acquisition Per Share Consideration | $ / shares |  |  |  |  |  | $ 5.79 |  |  |  |
Revett Mining Company, Inc. [Member] | Plant and Equipment [Member] |  |  |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total |  |  |  |  |  | $ 800 |  |  |  |
Revett Mining Company, Inc. [Member] | Land [Member] |  |  |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total |  |  |  |  |  | 100 |  |  |  |
Revett Mining Company, Inc. [Member] | Mineral Interests [Member] |  |  |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total |  |  |  |  |  | $ 73,400 |  |  |  |
Mines Management [Member] |  |  |  |  |  |  |  |  |  |
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |  |  |  |  |  |  |  |  | 32 |
Business Combination, Acquisition Related Costs, Shares Issued | shares |  |  |  |  | 181,048 |  |  |  |  |
Business Combination, Acquisition Related Costs |  |  |  |  |  |  |  |  | $ 4,700 |
Mines Management [Member] | Acquisition Costs [Member] |  |  |  |  |  |  |  |  |  |
Business Combination, Acquisition Related Costs |  |  |  |  | $ 1,000 |  |  |  |  |
Dolly Varden [Member] |  |  |  |  |  |  |  |  |  |
Business Acquisition, Share Price | $ / shares |  |  |  | $ 0.69 |  |  |  |  |  |
Business Combination, Consideration Transferred, Total |  |  |  | $ 13.6 |  |  |  |  |  |
Ownership Percentage |  |  |  | 100.00% |  |  |  |  |  |
Business Combination, Step Acquisition, Equity Interest in Acquiree, Shares | shares |  |  |  | 4,478,087 |  |  |  |  |  |
Business Combination, Step Acquisition, Equity Interest in Acquiree, Warrants | shares |  |  |  | 1,351,762 |  |  |  |  |  |
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage |  |  |  | 18.50% |  |  |  |  |  |

X
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- Definition In a business acquisition, the number of shares owned by a subsidiary of the company that are cancelled as a result of the acquisition. + References No definition available. + Details
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- Definition In a business acquisition, the number of the company's shares of common stock exchanged for each share of the acquiree's common stock. + References No definition available. + Details
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- Definition The share exchange rate if combined alternative option elected in a business combination. + References No definition available. + Details
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- Definition Represents the value of settlement of certain equity compensation in a business combination transaction. + References No definition available. + Details
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- Definition Number of acquiree's shares held by the acquirer immediately before the acquisition date in a business combination. + References No definition available. + Details
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- Definition Number of acquiree's shares into which warrants held by the acquirer may be converted immediately before the acquisition date. + References No definition available. + Details
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- Definition The value of common stock of a new formed company that are subscribed by the company. + References No definition available. + Details
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- Definition The number of warrants or rights issued during period. + References No definition available. + Details
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- Definition Value of warrants or rights issued during period. + References No definition available. + Details
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- Definition Number of shares of equity interests issued or issuable to acquire entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(4) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e1043-128460 + Details
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477 + Details
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- Definition Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477 + Details
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- Definition This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition The amount of property, plant, and equipment recognized as of the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 55 -Paragraph 37 -URI http://asc.fasb.org/extlink&oid=108330185&loc=d3e2207-128464 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472 + Details
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- Definition Percentage of equity in the acquiree held by the acquirer immediately before the acquisition date in a business combination. + References No definition available. + Details
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- Definition Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares. + References No definition available. + Details
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- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
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