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Note 6 - Business Segments and Sales of Products Note 7 - Employee Benefit Plans Note 8 - Stockholders' Equity Note 9 - Debt, Credit Facilities and Leases us-gaap_DerivativeGainOnDerivative Derivative, Gain on Derivative Note 11 - Derivative Instruments Note 12 - Fair Value Measurement Note 13 - Acquisition of Klondex Note 14 - Guarantor Subsidiaries us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables Accounts receivable Income Tax Disclosure [Text Block] us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther Other current assets Note 3 - Income Taxes - Major Components of Income Tax Provision (Benefit) (Details) Unrealized holding losses on investments Note 6 - Business Segments and Sales of Products - Information About Reportable Segments (Details) Hedging Designation [Axis] us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents Cash Note 6 - Business Segments and Sales of Products - Percentage of Sales by Segments (Details) Hedging Designation [Domain] Note 6 - Business Segments and Sales of Products - Sales of Products (Details) Designated as Hedging Instrument [Member] Current liabilities us-gaap_LiabilitiesCurrent Total current liabilities Note 6 - Business Segments and Sales of Products - Sales by Geographic Area (Details) Schedule of Maturities of Long-term Debt [Table Text Block] Note 6 - Business Segments and Sales of Products - Sales from Continuing Operations to Significant Metals Customers As a Percentage of Total Sales (Details) Note 7 - Employee Benefit Plans - Net Periodic Pension Cost (Details) Note 8 - Stockholders' Equity - Common Stock Dividend Policy (Details) Note 9 - Debt, Credit Facilities and Leases - Annual Future Obligations Related to the Senior Notes (Details) Other current liabilities us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Note 9 - Debt, Credit Facilities and Leases - Credit Facility (Details) Note 9 - Debt, Credit Facilities and Leases - Maturities of Finance Lease (Details) us-gaap_BusinessCombinationConsiderationTransferred1 Business Combination, Consideration Transferred, Total Total consideration Note 9 - Debt, Credit Facilities and Leases - Maturities of Operating Lease (Details) Current portion of accrued reclamation and closure costs us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance Note 11 - Derivative Instruments - Summary of Forward Sales Contracts (Details) Note 12 - Fair Value Measurement - Assets and Liabilities Accounted for at Fair Value (Details) Note 13 - Acquisition of Klondex - Preliminary Purchase Price Allocation (Details) Note 13 - Acquisition of Klondex - Preliminary Purchase Price Allocation (Details) (Parentheticals) Note 14 - Guarantor Subsidiaries - Unaudited Interim Condensed Consolidating Balance Sheets (Details) Note 14 - Guarantor Subsidiaries - Unaudited Interim Condensed Consolidating Statements of Operations (Details) Note 14 - Guarantor Subsidiaries - Unaudited Interim Condensed Consolidating Statements of Cash Flows (Details) Notes To Financial Statements Notes To Financial Statements [Abstract] us-gaap_BusinessAcquisitionSharePrice Business Acquisition, Share Price Other (expense) income us-gaap_OtherOperatingIncomeExpenseNet Other (expense) income us-gaap_DerivativeNumberOfInstrumentsHeld Derivative, Number of Instruments Held, Total us-gaap_DerivativeLiabilitiesCurrent Derivative Liability, Current us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired Business Acquisition, Percentage of Voting Interests Acquired Maturities of investments Gold [Member] Recognition of operating lease liabilities and right-of-use assets The amount of noncash recognition of operating lease liabilities and right-of-use assets. 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Accrued taxes Accrued payroll and related benefits Pension Plan [Member] Accrued interest Revolving Credit Facility [Member] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Credit Facility [Axis] Proceeds from disposition of properties, plants and equipment Supplemental Employee Retirement Plan [Member] Credit Facility [Domain] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] us-gaap_PolicyTextBlockAbstract Accounting Policies Common stock issued for 401(k) match The value of stock issued during period for a 401k match. us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements Incremental Common Shares Attributable to Share-based Payment Arrangements, Total us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Additions to properties, plants, equipment and mineral interests Additions to properties, plants, and equipment Common stock issued for 401(k) match, shares (in shares) The number of shares of stock issued during period for a 401k match. 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Such surety bonds may be for the purpose of, but not limited to, financial support for future reclamation and closure costs, self-insurance, and employee benefit plans. us-gaap_OperatingLeaseExpense Operating Lease, Expense (Loss) income applicable to common stockholders us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic (Loss) income applicable to common stockholders Hecla Warrants [Member] Information pertaining to Hecla Warrants. hl_ClassOfWarrantOrRightIssuedDuringPeriodValue Class of Warrant or Right, Issued During Period, Value Value of warrants or rights issued during period. us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards Share-based Payment Arrangement, Cash Used to Settle Award San Sebastian [Member] Reporting segment classified as San Sebastian. 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Lead 2019 Settlements for Provisional Sales [Member] Represents the 2019 settlements for provisional sales of lead. Zinc 2019 Settlements for Provisional Sales [Member] Represents the 2019 settlements for provisional sales of zinc. Gold 2019 Settlements for Provisional Sales [Member] Represents the 2019 settlements for provisional sales of gold. Silver 2019 Settlements for Provisional Sales [Member] Represents the 2019 settlements for provisional sales of silver. Amendment Flag Comprehensive (loss) income: Comprehensive (loss) income us-gaap_ComprehensiveIncomeNetOfTax Comprehensive (loss) income Cost of sales and Other Direct Production Costs [Member] Primary financial statement caption encompassing cost of sales and other direct production costs. hl_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayableAndAccruedLiabilities Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Accounts Payable and Accrued Liabilities This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to accounts payable and accrued liabilities assumed in connection with a business combination for which the initial accounting was incomplete. hl_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNoncurrentDeferredTaxLiability Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Noncurrent Deferred Tax Liability This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to noncurrent deferred tax liability assumed in connection with a business combination for which the initial accounting was incomplete. hl_EstimatedAlternativeResponseCosts Estimated Alternative Response Costs Represents the amount of estimated response costs that may be incurred. Adjustment to fair value of warrants issued for purchase of another company Amount of increase (decrease) in additional paid in capital (APIC) resulting from the adjustment to fair value of warrants issued for purchase of another entity. Includes allocation of proceeds of debt securities issued with detachable stock purchase warrants. Restricted Stock Units [Member] Information pertaining to restricted stock units. us-gaap_GainLossOnSaleOfPropertyPlantEquipment Gain on disposition of properties, plants, equipment, and mineral interests Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding, Ending Balance Series B preferred stock, shares outstanding (in shares) Johnny M Mine Area near San Mateo, New Mexico [Member] Responsibility under CERCLA for environmental remediation and past costs the EPA has incurred related to the Johnny M Mine Area near San Mateo, McKinley County, New Mexico. Gain on derivative contracts (Loss) gain on derivative contracts Gain (Loss) on Sale of Derivatives us-gaap_IncreaseDecreaseInOtherOperatingAssets Other current and non-current assets Current Fiscal Year End Date Variable rate us-gaap_DebtInstrumentInterestRateStatedPercentage Debt Instrument, Interest Rate, Stated Percentage JAPAN Document Fiscal Period Focus Document Fiscal Year Focus us-gaap_IncreaseDecreaseInDeferredIncomeTaxes Deferred income taxes Carpenter Snow Creek Superfund Site, Cascade County, Montana [Member] Responsibility under CERCLA for environmental remediation and past costs the EPA has incurred related to the Carpenter Snow Creek Superfund Site, Cascade County, Montana. Document Period End Date KOREA, REPUBLIC OF Entity Emerging Growth Company us-gaap_DebtInstrumentFaceAmount Debt Instrument, Face Amount hl_BusinessCombinationConsiderationCombinedAlternativeShareExchangeRate Business Combination Consideration, Combined Alternative, Share Exchange Rate The share exchange rate if combined alternative option elected in a business combination. Document Type hl_BusinessCombinationConsiderationCombinedAlternativePricePerShare Business Combination Consideration, Combined Alternative, Price Per Share Price of a single share payable by the company if the combined option is elected. Interim Period, Costs Not Allocable [Domain] Entity Small Business Document Information [Line Items] us-gaap_DividendsPreferredStock Series B Preferred Stock dividends declared ($0.875 per share) Preferred stock dividends Document Information [Table] Provision for closed operations and environmental matters Environmental Remediation Expense Nature of Expense [Axis] Entity Filer Category Entity Current Reporting Status us-gaap_DividendsCommonStock Dividends, Common Stock, Total Common stock dividends declared ($0.0025 per common share) Acquisition costs Acquisition costs London Interbank Offered Rate (LIBOR) [Member] Variable Rate [Domain] Variable Rate [Axis] us-gaap_IncreaseDecreaseInAccountsReceivable Accounts receivable Percentage of sales Significant metal customers Entity Central Index Key Entity Registrant Name Entity [Domain] Legal Entity [Axis] Customer Concentration Risk [Member] Scotia [Member] The entity Scotia. Other Geographic Areas [Member] Represents all other geographic areas not specifically disclosed. Concentration Risk Type [Axis] us-gaap_AllowanceForDoubtfulAccountsReceivable Accounts Receivable, Allowance for Credit Loss, Ending Balance us-gaap_TreasuryStockValue Less treasury stock, at cost; March 31, 2019 and December 31, 2018 - 5,226,791 shares issued and held in treasury Concentration Risk Type [Domain] us-gaap_StockRepurchasedDuringPeriodShares Stock Repurchased During Period, Shares Entity Common Stock, Shares Outstanding (in shares) Revenue Benchmark [Member] Amortization of prior service cost us-gaap_IncreaseDecreaseInInventories Inventories us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses Amortization of net loss Revenue from Contract with Customer Benchmark [Member] Trading Symbol us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost Net periodic pension cost Service cost Concentration Risk Benchmark [Axis] Interest cost Concentration Risk Benchmark [Domain] us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets Expected return on plan assets Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] us-gaap_TableTextBlock Notes Tables us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity hl_OwnershipPercentage Ownership Percentage Percentage of ownership in properties. Restricted stock units granted Standby fee per annum on undrawn amounts Related Party [Axis] Exploration Represents the amount of exploration costs recorded during the period related to mining activities. Related Party [Domain] hl_IncreaseDecreaseInAccruedReclamationAndClosureCostsAndOtherNonCurrentLiabilities Accrued reclamation and closure costs and other non-current liabilities Increase decrease in accrued reclamation and closure costs and other non-current liabilities. Common stock issued for employee incentive compensation, shares (in shares) Common stock issued for employee incentive compensation 1,237,369 shares) us-gaap_StockIssuedDuringPeriodSharesNewIssues Stock Issued During Period, Shares, New Issues Schedule of Line of Credit Facilities [Table Text Block] Total liabilities and shareholders' equity us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and stockholders’ equity us-gaap_StockIssuedDuringPeriodValueNewIssues Stock Issued During Period, Value, New Issues Other operating expense UNITED STATES Research and development Research and development Accumulated deficit Accumulated other comprehensive loss Schedule of Potential Per Share Dividend Amounts Quarterly Price Levels [Table Text Block] Schedule summarizing the potential per share dividend amounts at different quarterly average realized price levels. Debt Disclosure [Text Block] Quarterly average realized silver price per ounce (in USD per Ounce) Represents the quarterly average realized silver price. us-gaap_InterestExpense Interest expense us-gaap_InterestExpenseDebt Interest Expense, Debt, Total hl_AverageRealizedSilverPriceMinimumDividendThreshold Average Realized Silver Price, Minimum Dividend, Threshold The minimum average realized silver price per ounce that must be met for the silver-price-linked component of dividends to be declared. 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Current portion of finance leases Finance Lease, Liability, Current Pension and Other Postretirement Benefits Disclosure [Text Block] Non-current finance leases Finance Lease, Liability, Noncurrent Operating lease right-of-use assets Operating Lease, Right-of-Use Asset us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Lessee, Operating Lease, Liability, Payments, Due, Total Total Finance lease liability Finance Lease, Liability, Total us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount Effect of discounting us-gaap_FinanceLeasePrincipalPayments Repayments of finance leases us-gaap_DeferredIncomeTaxExpenseBenefit Total deferred income tax benefit (provision) Provision for reclamation and closure costs us-gaap_FinanceLeaseRightOfUseAsset Finance Lease, Right-of-Use Asset Unrealized gain on investments Unrealized gain on investments us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour 2023 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive 2024 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive More than 5 years us-gaap_DerivativeAssetsNoncurrent Derivative Assets, Noncurrent, Total us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths 2020 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo 2021 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree 2022 Payment of accrued compensation in stock Lessee, Operating Lease, Liability, Maturity [Table Text Block] Stock compensation Other non-current assets Other operating expenses: Total assets us-gaap_AssetsFairValueDisclosure Quarterly Average Realized Price, Level 1 [Member] Represents the first quarterly average realized silver price per ounce level. us-gaap_EquitySecuritiesFvNiCost Equity Securities, FV-NI, Cost Non-current investments Depreciation, depletion and amortization us-gaap_DepreciationDepletionAndAmortization Total liabilities us-gaap_LiabilitiesFairValueDisclosure us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Foreign exchange contracts us-gaap_ForeignCurrencyContractAssetFairValueDisclosure us-gaap_SharesIssuedPricePerShare Stock Issued, per share (in dollars per share) Foreign exchange contracts us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure us-gaap_AssetsCurrent Total current assets Stockholders' Equity Note Disclosure [Text Block] Zinc 2020 Settlements for Forecasted Sales [Member] Represents the 2020 settlements for forecasted sales of zinc. Lead 2020 Settlements for Forecasted Sales [Member] Represents the 2020 settlements for forecasted sales of Lead. Taxes Treasury stock, shares (in shares) Treasury Stock, Shares, Ending Balance Common stock, $0.25 par value, 750,000,000 shares authorized; issued and outstanding March 31, 2019 — 482,987,752 shares and December 31, 2018 — 482,603,937 shares Senior Notes [Member] Quarterly Average Realized Price, Level 3 [Member] Represents the third quarterly average realized silver price per ounce level. Quarterly Average Realized Price, Level 4 [Member] Represents the fourth quarterly average realized silver price per ounce level. Non-cash elements included in net (loss) income: Measurement Frequency [Axis] Measurement Frequency [Domain] Quarterly Average Realized Price, Level 2 [Member] Represents the second quarterly average realized silver price per ounce level. Fair Value, Recurring [Member] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued, Total Quarterly Average Realized Price, Level 5 [Member] Represents the fifth quarterly average realized silver price per ounce level. us-gaap_LesseeOperatingLeaseDiscountRate Lessee, Operating Lease, Discount Rate Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share us-gaap_PensionContributions Payment for Pension Benefits Suspension-related costs Employee Labor Strike Related Costs Amount of expenses associated with a labor strike by a portion of the reporting entity's workforce. us-gaap_DerivativeAssetsCurrent Derivative Asset, Current Statistical Measurement [Domain] Maximum [Member] Significant non-cash investing and financing activities: Minimum [Member] Ownership [Domain] Product and Service [Axis] Other current assets Non-current deferred income taxes Product and Service [Domain] Statistical Measurement [Axis] Series B preferred stock, liquidation preference Litigation Case [Axis] Litigation Case [Domain] Ownership [Axis] us-gaap_PaymentsForBrokerageFees Payments for Brokerage Fees Preferred stock, 5,000,000 shares authorized: Series B preferred stock, $0.25 par value, 157,816 shares issued and outstanding, liquidation preference — $7,891 Series B preferred stock, shares issued (in shares) Prepaid taxes us-gaap_NoncurrentAssets Long-Lived Assets Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block] Geographical [Axis] hl_MetalsContainedInConcentrates Metals Contained in Concentrates Represents the metals contained in concentrates. Geographical [Domain] Preferred stock, shares authorized (in shares) Unsettled Concentrate Sales Contracts [Member] Unsettled concentrate sales contracts [member Series B preferred stock, par value (in dollars per share) Forecasted Future Concentrate Contracts [Member] Forecasted future concentrate contracts [member Net sales Sales of products Revenue from External Customers by Products and Services [Table Text Block] us-gaap_ForeignCurrencyTransactionGainLossBeforeTax Foreign exchange loss (gain) Concentrates, doré, and stockpiled ore Currency [Axis] Fair Value Hierarchy and NAV [Domain] Customer [Axis] Fair Value, Inputs, Level 1 [Member] Customer [Domain] Fair Value, Inputs, Level 2 [Member] Lead 2019 Settlements for Forecasted Sales [Member] Represents information pertaining to the 2019 settlements for forecasted sales of lead. Fair Value Hierarchy and NAV [Axis] Zinc 2019 Settlements for Forecasted Sales [Member] Represents information pertaining to the 2019 settlements for forecasted sales of zinc. Materials and supplies Inventories: Operating activities: Schedule of Segment Reporting Information, by Segment [Table Text Block] Statement [Line Items] Sales by significant product type hl_SalesRevenueGoodsExcludingGainLossOnForwardContracts Sales by geographical area Sales revenue goods excluding gain loss on forward contracts. Trade Accounts Receivable, after Allowance for Credit Loss, Current, Total hl_LetterOfCreditParticipationFeePercent Letter of Credit, Participation Fee, Percent The percentage of required participation fee on the letter of credit. us-gaap_NumberOfReportableSegments Number of Reportable Segments Capital surplus hl_LetterOfCreditOutstandingFrontingFee Letter of Credit Outstanding, Fronting Fee Percentage of fronting fee to each issuing bank annually on the average dollar amount of any outstanding letters of credit. Accounts receivable: AOCI Attributable to Parent [Member] STOCKHOLDERS’ EQUITY Teck Metals Ltd [Member] The entity Teck Metals Ltd. Korea Zinc [Member] The entity Korea Zinc. Other expense Trafigura AG [Member] Trafigura AG us-gaap_NonoperatingIncomeExpense Total other expense Segment Reporting Disclosure [Text Block] CIBC [Member] The entity CIBC. Current assets: Fair Value Disclosures [Text Block] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations Cash, cash equivalents and restricted cash and cash equivalents at beginning of period Cash, cash equivalents and restricted cash and cash equivalents at end of period Assets Effect of exchange rates on cash Changes in cash, cash equivalents and restricted cash and cash equivalents us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect Net (decrease) increase in cash, cash equivalents and restricted cash and cash equivalents us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash (used in) provided by financing activities us-gaap_Liabilities Total liabilities Commitments and contingencies (Notes 2, 4, 7, 9, and 11) Income (loss) from operations (Loss) income from operations invest_DerivativeNotionalAmount Derivative, Notional Amount Cash flows from operating activities us-gaap_NetCashProvidedByUsedInOperatingActivities Cash provided by operating activities Other income (expense): us-gaap_DeferredTaxLiabilities Deferred Tax Liabilities, Net, Total us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities Non-current pension liability Effect of exchange rate changes on cash us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions us-gaap_GrossProfit Gross profit Base Rate [Member] us-gaap_CostOfGoodsAndServicesSold Total cost of sales Consolidation, Eliminations [Member] 2021 (principal and interest) Amount of long-term debt payable, sinking fund requirements, and other securities including interest issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. 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Excludes capital lease obligations. hl_LongtermDebtObligationsInterest Less: interest Interest attributed to long term debt obligations. Metal forward contracts us-gaap_DerivativeLiabilities Consolidation Items [Axis] Parent Company [Member] Other financing activity us-gaap_ProceedsFromPaymentsForOtherFinancingActivities Subsidiaries [Member] Guarantor Subsidiaries [Member] Non-Guarantor Subsidiaries [Member] Consolidated Entities [Axis] Consolidated Entities [Domain] us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation Payment, Tax Withholding, Share-based Payment Arrangement us-gaap_LettersOfCreditOutstandingAmount Letters of Credit Outstanding, Amount hl_DerivativeFairValueObligationsUnderTheAgreements Derivative, Fair Value, Obligations Under the Agreements The amount of required settlement obligation under the agreements at termination. Condensed Cash Flow Statement [Table Text Block] us-gaap_PaymentsOfDividends Dividends paid to stockholders Condensed Balance Sheet [Table Text Block] Condensed Income Statement [Table Text Block] us-gaap_PaymentsOfDividendsCommonStock Dividends paid to common stockholders us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock Dividends paid to preferred stockholders Warrants in Connection with Klondex Mines Acquisition [Member] Information related to warrants in connection with the Klondex Mines Acquisition. hl_ClassOfWarrantOrRightIssuedDuringPeriod Class of Warrant or Right, Issued During Period The number of warrants or rights issued during period. hl_ForecastedCADDenominatedOperatingCostsToBeHedgedTerm Forecasted CAD-denominated Operating Costs to be Hedged, Term Period within which forecasted CAD (Canadian dollar) denominated operating costs will be hedged. hl_MaximumAllocationOfForecastedCADDemonimatedOperatingCosts Maximum Allocation of Forecasted CAD-demonimated Operating Costs Represents the maximum percentage of CAD (Canadian dollar) denominated operating costs to be hedged in the future. Depreciation, depletion and amortization Depreciation, depletion, amortization Warrants in Connection with Klondex Mines Acquisition Expiring February 2029 [Member] Information related to warrants in connection with the Klondex Mines acquisition expiring February 2029. Warrants in Connection with Klondex Mines Acquisition Expiring April 2032 [Member] Information related to warrants in connection with the Klondex Mines acquisition that expire April 2032. us-gaap_PaymentsForRepurchaseOfCommonStock Acquisition of treasury shares Scenario [Domain] Forecast [Member] Retained Earnings [Member] Series 2018-A Senior Notes [Member] Represents the information pertaining to Series 2018-A Senior Notes. hl_DebtInstrumentIssuanceDiscountRate Debt Instrument, Issuance, Discount Rate Represents the discount rate for debt instrument issued. us-gaap_TreasuryStockAcquiredAverageCostPerShare Treasury Stock Acquired, Average Cost Per Share Treasury Stock [Member] Scenario [Axis] us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased us-gaap_CurrentForeignTaxExpenseBenefit Foreign us-gaap_DeferredForeignIncomeTaxExpenseBenefit Foreign Additional Paid-in Capital [Member] Share Repurchase Program [Domain] Common Stock [Member] us-gaap_CurrentFederalTaxExpenseBenefit Domestic Preferred Stock [Member] us-gaap_DeferredFederalIncomeTaxExpenseBenefit Domestic us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased Stock Repurchase Program, Number of Shares Authorized to be Repurchased Equity Components [Axis] Equity Component [Domain] Share Repurchase Program [Axis] Investment [Text Block] us-gaap_CurrentIncomeTaxExpenseBenefit Total current income tax benefit (provision) Environmental Remediation Site [Domain] hl_EstimatedMineLife Estimated Mine Life The estimated mine life for mining properties. Other Noncurrent Assets [Member] us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 Class of Warrant or Right, Exercise Price of Warrants or Rights Class of Warrant or Right [Axis] Other Current Liabilities [Member] Class of Warrant or Right [Domain] Other Noncurrent Liabilities [Member] us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight Class of Warrant or Right, Number of Securities Called by Each Warrant or Right us-gaap_NotesPayable Notes Payable, Total Environmental Remediation Site [Axis] us-gaap_ClassOfWarrantOrRightOutstanding Class of Warrant or Right, Outstanding Other Current Assets [Member] hl_SmelterAndRefiningCharges Less: Smelter and refining charges The costs of extracting metal from ore. Bulk Concentrate [Member] Represents the information pertaining to bulk concentrate. Zinc Concentrate [Member] Represents the information pertaining to zinc concentrate. Mexican Tax Authority [Member] Lead Concentrate [Member] Represents the information pertaining to lead concentrate. Doré and Metals from Doré [Member] Represents doré and metals from doré, a doré bar is a semi-pure alloy of gold and silver, usually created at the site of a mine. It is then transported to a refinery for further purification. Ocean Partners [Member] Represents Ocean Partners, a major customer of the company. us-gaap_LineOfCredit Long-term Line of Credit, Total us-gaap_PaymentsOfDebtIssuanceCosts Credit facility fees paid Zinc 2018 Settlements for Provisional Sales [Member] Represents the 2018 settlements for provisional sales of zinc. Other current assets hl_OtherCurrentAssets Represents the amount of other current assets including investments, accounts receivables and inventories. Other non-current assets hl_OtherNonCurrentAssets Represents the amount of other non-current assets including long-term investments, restricted cash and deferred income taxes. Pre-development Represents the amount of predevelopment costs recorded during the period. hl_BusinessCombinationConsiderationCashAlternativePricePerShare Business Combination, Consideration, Cash Alternative, Price Per Share Price of a single share payable by the company if the cash option is elected. Income Tax Authority, Name [Axis] Klondex Mines Ltd [Member] Represents the information pertaining to Klondex Mines Ltd. Income Tax Authority, Name [Domain] Internal Revenue Service (IRS) [Member] hl_PaymentOfResponseCosts Payment Of Response Costs Represents the amount of response costs paid during the period. Other non-current liabilities hl_OtherNonCurrentLiabilities Represents the amount of other non-current liabilities including pension liabilities. Income Tax Authority [Axis] hl_EstimatedResponseCosts Estimated Response Costs Represents the estimated amount of response costs that have been incurred by the EPA in cleaning up a site. Income Tax Authority [Domain] hl_EstimatedFutureResponseCost Estimated Future Response Cost Represents the estimated future response cost that the EPA may ultimately incur related to a site. Domestic Tax Authority [Member] hl_BusinessCombinationConsiderationShareAlternativeShareExchangeRate Business Combination, Consideration, Share Alternative, Share Exchange Rate The share exchange rate if share exchange option elected in a business combination. Foreign Tax Authority [Member] hl_OpenPurchaseOrders Open Purchase Orders Represents the amount of open purchase orders as of a specified date. Non-cash Depreciation Expense [Member] Information pertaining to non-cash depreciation expense. us-gaap_RepaymentsOfLongTermDebtAndCapitalSecurities Payments on debt hl_AverageRealizedSilverPrice Average Realized Silver Price Represents the average silver price realized during the period. Quarterly dividend per share (in dollars per share) Represents the quarterly dividend per share. Annual dividend per share (in dollars per share) Represents the annual dividend per share. hl_UnderwritingDiscountOnSeniorNotes Underwriting Discount on Senior Notes Represents the underwriting discount on senior notes. Balance Sheet Location [Axis] hl_BusinessCombinationSubscritionOfNewFormedCompanyValue Business Combination, Subscrition of New Formed Company, Value The value of common stock of a new formed company that are subscribed by the company. Balance Sheet Location [Domain] us-gaap_DebtInstrumentUnamortizedDiscountNoncurrent Less: unamortized discount us-gaap_DebtInstrumentUnamortizedDiscount Debt Instrument, Unamortized Discount, Total us-gaap_DebtInstrumentCarryingAmount Principal Accounting Policies [Abstract] Schedules of Concentration of Risk, by Risk Factor [Table Text Block] us-gaap_CommonStockDividendsPerShareDeclared Common Stock, Dividends, Per Share, Declared Common stock dividends declared, per share (in dollars per share) Other Nonoperating Income (Expense) [Member] Guarantor Subsidiaries [Text Block] Guarantor subsidiaries text block. Long-term debt us-gaap_LongTermDebtAndCapitalLeaseObligations Cost of sales and other direct production costs Cost of sales The costs related to goods produced and sold during the reporting period, before depreciation, depletion, and amortization. hl_ExplorationAndPredevelopmentCosts Exploration and pre-development Exploration and predevelopment costs. Borrowings on debt us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt Proceeds from Issuance of Senior Long-term Debt Revenues Revenues Amount, including tax collected from customer, of revenue (expense) from satisfaction of performance obligation by transferring promised good or service to customer. Income Statement Location [Axis] Income Statement Location [Domain] Segments [Axis] Segments [Domain] us-gaap_ContractualObligation Contractual Obligation, Total Other Segments [Member] us-gaap_SharePrice Share Price us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Change in accounting for marketable equity securities Represents the reclassification from retained earnings to AOCI during the period related to the adoption of an accounting standards update. us-gaap_RepaymentsOfLinesOfCredit Repayments of Lines of Credit Weighted average number of common shares outstanding - diluted (in shares) us-gaap_EarningsPerShareBasicAndDiluted Earnings Per Share, Basic and Diluted, Total us-gaap_ProceedsFromLinesOfCredit Proceeds from Lines of Credit, Total Statement [Table] Statement of Financial Position [Abstract] Diluted (loss) income per common share after preferred dividends (in dollars per share) Weighted average number of common shares outstanding - basic (in shares) Business Acquisition [Axis] Basic (loss) income per common share after preferred dividends (in dollars per share) Business Acquisition, Acquiree [Domain] Deferred Shares [Member] Represents information about deferred shares. Statement of Cash Flows [Abstract] Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block] Statement of Stockholders' Equity [Abstract] Preferred stock dividends declared, per share (in dollars per share) Income Statement [Abstract] Changes in comprehensive (loss) income Other comprehensive income (loss) us-gaap_DerivativeFairValueOfDerivativeLiabilityAmountNotOffsetAgainstCollateral Derivative Liability, Fair Value, Amount Not Offset Against Collateral, Total Lucky Friday [Member] Reporting segment classified as Lucky Friday. us-gaap_ProceedsFromIssuanceOfDebt Proceeds from Issuance of Debt Greens Creek [Member] Reporting segment classified as Greens Creek. Casa Berardi [Member] Reporting segment classified as Casa Berardi. us-gaap_RepaymentsOfDebt Repayments of debt us-gaap_FinanceLeaseInterestExpense Finance Lease, Interest Expense us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued Business Acquisition, Equity Interest Issued or Issuable, Number of Shares us-gaap_FinanceLeaseLiabilityPaymentsDue Finance Lease, Liability, Payment, Due, Total Total us-gaap_FinanceLeaseRightOfUseAssetAmortization Finance Lease, Right-of-Use Asset, Amortization us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInventory Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount Finance Lease, Liability, Undiscounted Excess Amount Less: imputed interest Performance Obligation Commitments [Member] Commitments relating to performance obligations. Lawsuit in Lincoln County, Montana Courts for Montanore Project [Member] Information regarding the lawsuit in the court of Lincoln County, Montana relating to the Montanore project. us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearFour 2023 Equity securities – mining industry us-gaap_AvailableForSaleSecuritiesEquitySecurities us-gaap_FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths 2020 Money market funds and other bank deposits us-gaap_DepositsMoneyMarketDeposits New Accounting Pronouncements and Changes in Accounting Principles [Text Block] us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearTwo 2021 us-gaap_FinanceLeaseLiabilityPaymentsDueInRollingYearThree 2022 Finance Lease, Liability, Maturity [Table Text Block] Other Commitments [Axis] Other Commitments [Domain] us-gaap_PaymentsForProceedsFromOtherInvestingActivities Other investing activities, net Financing activities: Change in fair value of derivative contracts designated as hedge transactions Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Other non-current liabilities Non-current deferred tax liability Non-current deferred tax liability us-gaap_DerivativeLiabilitiesNoncurrent Derivative Liability, Noncurrent Nevada Operations [Member] Represents information about Nevada Operations. Dividends [Axis] Dividends [Domain] hl_CommonStockAggregateOfferingPrice Common Stock, Aggregate Offering Price Represents the common stock aggregate offering price. Accrued reclamation and closure costs us-gaap_MineReclamationAndClosingLiabilityNoncurrent us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet Net assets hl_BusinessCombinationSettlementOfCertainEquityCompensationValue Business Combination, Settlement of Certain Equity Compensation Value Represents the value of settlement of certain equity compensation in a business combination transaction. hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedMineralInterest Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Mineral Interest The amount of mineral interest recognized as of the acquisition date. hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventoryFinishedGoodsInProcessMaterialAndStockpiledOre Inventory - finished goods, in-process material and stockpiled ore The amount of inventory, in-process material and stockpiled ore recognized as of the acquisition date. hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventorySupplies Inventory - supplies The amount of inventory, supplies recognized as of the acquisition date. Stockholders' equity us-gaap_StockholdersEquity Total stockholders’ equity Balance Balance us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities Total liabilities hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedPayrollAndRelatedBenefits Accrued payroll and related benefits The amount of accrued payroll and related benefits recognized as of the acquisition date. hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonCurrentRestrictedCashAndInvestments Non-current restricted cash and investments The amount of non-current restricted cash and investments recognized as of the acquisition date. hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDepletableMineralInterest Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Depletable Mineral Interest The amount of depletable mineral interests recognized as of the acquisition date. hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonCurrentInvestments Non-current investments The amount of non-current investments recognized as of the acquisition date. us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation Lease liability Class of Stock [Axis] hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetRetirementObligation Asset retirement obligation The amount of asset retirement obligation recognized as of the acquisition date. us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent Deferred tax liability Long-term debt Long-term debt hl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccruedTaxes Accrued taxes The amount of accrued taxes recognized as of the acquisition date. us-gaap_PaymentsToAcquireBusinessesGross Payments to Acquire Businesses, Gross us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt Debt us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets Total assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable Accounts payable and accrued liabilities Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Waterton Warrants [Member] Represents information about Waterton warrants. us-gaap_DerivativeForwardExchangeRate1 Derivative, Forward Exchange Rate us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment Properties, plants, equipment and mineral interests