| Document And Entity Information - USD ($) | Dec. 31, 2019 | Feb. 06, 2020 | Jun. 30, 2019 |
| Document Information [Line Items] | |||
| Entity, Registrant Name | HECLA MINING COMPANY | ||
| Current Fiscal Year End Date | --12-31 | ||
| Document, Fiscal Period Focus | FY | ||
| Document, Fiscal Year Focus | 2019 | ||
| Document, Type | 10-K/A | ||
| Document, Annual Report | true | ||
| Document, Period End Date | Dec. 31, 2019 | ||
| Document, Transition Report | false | ||
| Entity, File Number | 1-8491 | ||
| Entity, Incorporation, State or Country Code | DE | ||
| Entity, Tax Identification Number | 77-0664171 | ||
| Entity, Address, Address Line One | 6500 N. Mineral Drive, Suite 200 | ||
| Entity, Address, City or Town | Coeur d’Alene | ||
| Entity, Address, State or Province | ID | ||
| Entity, Address, Postal Zip Code | 83815-9408 | ||
| City Area Code | 208 | ||
| Local Phone Number | 769-4100 | ||
| Entity, Well-known Seasoned Issuer | Yes | ||
| Entity, Voluntary Filers | No | ||
| Entity, Current Reporting Status | Yes | ||
| Entity, Interactive Data, Current | Yes | ||
| Entity, Filer Category | Large Accelerated Filer | ||
| Entity, Small Business | false | ||
| Entity, Emerging Growth Company | false | ||
| Entity, Shell Company | false | ||
| Entity, Public Float | $ 868,456,633 | ||
| Entity, Common Stock Shares, Outstanding | 523,216,426 | ||
| Amendment Description | This Amendment No. 1 to Form 10-K (this “Amendment”) amends the Annual Report on Form 10-K for the fiscal year ended December 31, 2019, originally filed by Hecla Mining Company (the “Company”) on February 10, 2020 (the “Original Filing”). Due to a clerical error, the Company reported an incorrect number of shares outstanding on the cover page of the Original Filing. This Amendment corrects the number of shares outstanding on the cover page and updates Item 15 of Part II of the Original Filing to reflect the additions of Exhibits 31.3 and 31.4, which are filed with this Amendment. Except as described in this Explanatory Note, no other changes have been made to the Original Filing. The Original Filing continues to speak as of its filing date, and we otherwise have not updated the Original Filing to reflect any events which occurred subsequent to the filing date of the Original Filing. | ||
| Amendment Flag | true | ||
| Entity, Central Index Key | 0000719413 | ||
| CommonStock Custom [Member] | |||
| Document Information [Line Items] | |||
| Title of 12(b) Security | Common Stock | ||
| Trading Symbol | HL | ||
| Security Exchange Name | NYSE | ||
| SeriesBCumulativeConvertiblePreferredStock Custom [Member] | |||
| Document Information [Line Items] | |||
| Title of 12(b) Security | Series B Cumulative Convertible Preferred Stock | ||
| Trading Symbol | HL-PB | ||
| Security Exchange Name | NYSE |
