Note 1 - Basis of Preparation of Financial Statements	3 Months Ended
Mar. 31, 2020
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]	Note 1. Basis of Preparation of Financial Statements In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements and notes to the unaudited interim condensed consolidated financial statements contain all adjustments, consisting of normal recurring items and items which are nonrecurring, necessary to present fairly, in all material respects, the financial position of Hecla Mining Company and its consolidated subsidiaries (in this report, "Hecla" or "the Company" or “we” or “our” or “us” refers to Hecla Mining Company and our subsidiaries, unless the context requires otherwise). These unaudited interim condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and related footnotes as set forth in our annual report filed on Form 10-K for the year ended December 31, 2019, as it may be amended from time to time. The results of operations for the periods presented may not be indicative of those which may be expected for a full year. The unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and footnote disclosures normally included in audited financial statements prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) have been condensed or omitted pursuant to those rules and regulations, although we believe that the disclosures are adequate for the information not to be misleading. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements, the reported amounts of revenues and expenses during the reporting period, and the disclosures of contingent liabilities. Accordingly, ultimate results could differ materially from those estimates. The 2019 novel strain of coronavirus ("COVID-19") was characterized as a global pandemic by the World Health Organization on March 11, 2020, and COVID-19 has resulted in travel restrictions and business slowdowns or shutdowns in affected areas. In late March 2020, the Government of Quebec ordered the mining industry to reduce to minimum operations as part of the fight against the COVID-19 virus, causing us to suspend our Casa Berardi operations from approximately March 24 until April 15, when limited mining operations resumed. In early April, the Government of Mexico issued a similar order causing us to suspend our San Sebastian operations through April 30, and the order was subsequently extended to May 30. In addition, restrictions imposed by the State of Alaska in late March have caused us to revise the normal operating procedures for staffing operations at Greens Creek. These suspension orders impacted us in the first quarter of 2020 by curtailing our expected production of gold at Casa Berardi by approximately 5,200 ounces, along with the related revenue, and we anticipate our gold production and revenue at Casa Berardi will be impacted in the second quarter of 2020 at a similar or slightly higher level. We continued to incur costs at Casa Berardi while operations were suspended and will also incur suspension costs at San Sebastian, although at lower levels than during full production. At Casa Berardi, suspension costs in the first quarter of 2020 totaled $0.9 million. In addition, we have incurred costs of approximately $0.2 million per week related to quarantining employees at Greens Creek, which started in late March 2020. It is possible that the changes at Casa Berardi, San Sebastian or Greens Creek (or at any other operation) could continue to have an adverse impact on operations or 2020 financial results, including materially so, beyond the second quarter of 2020 if restrictions continue longer than anticipated or become broader. We have taken precautionary measures to mitigate the impacts of COVID-19, including implementing operational plans and practices and increasing our cash reserves through a draw-down of our revolving credit facility (see Note 9 for more information). As long as they are required, the operational practices implemented could have an adverse impact on our operating results due to deferred production and revenues or additional costs. We continue to monitor the rapidly evolving situation and guidance from federal, state, local and foreign governments and public health authorities and may take additional actions based on their recommendations. The extent of the impact of COVID-19 on our business and financial results will also depend on future developments, including the duration and spread of the outbreak within the markets in which we operate and the related impact on prices, demand, creditworthiness and other market conditions and governmental reactions, all of which are highly uncertain.

Note 1 - Basis of Preparation of Financial Statements

3 Months Ended

Mar. 31, 2020

Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]

Note 1. Basis of Preparation of Financial Statements

In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements and notes to the unaudited interim condensed consolidated financial statements contain all adjustments, consisting of normal recurring items and items which are nonrecurring, necessary to present fairly, in all material respects, the financial position of Hecla Mining Company and its consolidated subsidiaries (in this report, "Hecla" or "the Company" or “we” or “our” or “us” refers to Hecla Mining Company and our subsidiaries, unless the context requires otherwise). These unaudited interim condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and related footnotes as set forth in our annual report filed on Form 10-K for the year ended December 31, 2019, as it may be amended from time to time.

The results of operations for the periods presented may not be indicative of those which may be expected for a full year. The unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and footnote disclosures normally included in audited financial statements prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) have been condensed or omitted pursuant to those rules and regulations, although we believe that the disclosures are adequate for the information not to be misleading.

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements, the reported amounts of revenues and expenses during the reporting period, and the disclosures of contingent liabilities. Accordingly, ultimate results could differ materially from those estimates.

The 2019 novel strain of coronavirus ("COVID-19") was characterized as a global pandemic by the World Health Organization on March 11, 2020, and COVID-19 has resulted in travel restrictions and business slowdowns or shutdowns in affected areas. In late March 2020, the Government of Quebec ordered the mining industry to reduce to minimum operations as part of the fight against the COVID-19 virus, causing us to suspend our Casa Berardi operations from approximately March 24 until April 15, when limited mining operations resumed. In early April, the Government of Mexico issued a similar order causing us to suspend our San Sebastian operations through April 30, and the order was subsequently extended to May 30. In addition, restrictions imposed by the State of Alaska in late March have caused us to revise the normal operating procedures for staffing operations at Greens Creek. These suspension orders impacted us in the first quarter of 2020 by curtailing our expected production of gold at Casa Berardi by approximately 5,200 ounces, along with the related revenue, and we anticipate our gold production and revenue at Casa Berardi will be impacted in the second quarter of 2020 at a similar or slightly higher level. We continued to incur costs at Casa Berardi while operations were suspended and will also incur suspension costs at San Sebastian, although at lower levels than during full production. At Casa Berardi, suspension costs in the first quarter of 2020 totaled $0.9 million. In addition, we have incurred costs of approximately $0.2 million per week related to quarantining employees at Greens Creek, which started in late March 2020. It is possible that the changes at Casa Berardi, San Sebastian or Greens Creek (or at any other operation) could continue to have an adverse impact on operations or 2020 financial results, including materially so, beyond the second quarter of 2020 if restrictions continue longer than anticipated or become broader.

We have taken precautionary measures to mitigate the impacts of COVID-19, including implementing operational plans and practices and increasing our cash reserves through a draw-down of our revolving credit facility (see Note 9 for more information). As long as they are required, the operational practices implemented could have an adverse impact on our operating results due to deferred production and revenues or additional costs. We continue to monitor the rapidly evolving situation and guidance from federal, state, local and foreign governments and public health authorities and may take additional actions based on their recommendations. The extent of the impact of COVID-19 on our business and financial results will also depend on future developments, including the duration and spread of the outbreak within the markets in which we operate and the related impact on prices, demand, creditworthiness and other market conditions and governmental reactions, all of which are highly uncertain.