XML 71 R38.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Note 1 - Summary of Significant Accounting Policies (Details) $ in Thousands | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2015 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) oz T | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Capitalized Drilling Costs |  |  | $ 6,700 | $ 5,300 | $ 8,000
Number of Defined Contribution Plans Maintained |  |  | 2 |  |
Environmental Exit Costs, Costs Accrued to Date |  |  | $ 95,500 |  |
Foreign Currency Transaction Gain (Loss), Realized |  |  | 24,551 | 11,535 | 2,959
Share-based Compensation |  |  | 5,425 | 4,965 | 4,461
Deferred Tax Assets, Net of Valuation Allowance, Current |  |  | $ 17,980 | 12,029 |
Defined Benefit Pension Plan [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Pension Contributions | $ 4,900 |  |  | 6,500 |
Silver [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Metals Contained in Concentrates | oz |  |  | 1,500,000 |  |
Gold [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Metals Contained in Concentrates | oz |  |  | 5,605 |  |
Zinc [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Metals Contained in Concentrates | T |  |  | 12,714 |  |
Lead [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Metals Contained in Concentrates | T |  |  | 4,553 |  |
Scenario, Forecast [Member] | Defined Benefit Pension Plan [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year |  | $ 5,300 |  |  |
Unfunded Supplemental Executive Retirement Plan [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Pension Contributions |  |  | $ 400 | $ 300 | 300
Unfunded Supplemental Executive Retirement Plan [Member] | Scenario, Forecast [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Pension Contributions |  | $ 400 |  |  |
Defined Benefit Pension Plan [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Pension Contributions |  |  |  |  | $ 1,000
Minimum [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 1 year |  |
Maximum [Member] |  |  |  |  |
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items] |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 22 years |  |

X
- Definition Drilling and related costs. + References No definition available. + Details
Name: | hl_CapitalizedDrillingCosts
Namespace Prefix: | hl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Types of metal contained in concentrates. + References No definition available. + Details
Name: | hl_MetalsContainedInConcentrates
Namespace Prefix: | hl_
Data Type: | num:weightItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | hl_Note1SummaryofSignificantAccountingPoliciesDetailsLineItems
Namespace Prefix: | hl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total number of defined contribution plans the legal entity maintains. + References No definition available. + Details
Name: | hl_NumberOfDefinedContributionPlansMaintained
Namespace Prefix: | hl_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31917-109318 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31931-109318 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31928-109318 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 45 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31958-109318 + Details
Name: | us-gaap_DeferredTaxAssetsNetCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of the liability for remediation, site restoration, postclosure, monitoring commitments, or other exit costs associated with the sale, disposal or abandonment of a particular property resulting from unanticipated contamination of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 5.Y.Q4) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section Y -Paragraph Question 4 + Details
Name: | us-gaap_EnvironmentalExitCostsCostsAccruedToDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before tax of foreign currency transaction realized gain (loss) recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30690-110894 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30700-110894 + Details
Name: | us-gaap_ForeignCurrencyTransactionGainLossRealized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of cash or cash equivalents contributed by the entity to fund its pension plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585 + Details
Name: | us-gaap_PensionContributions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 + Details
Name: | us-gaap_ShareBasedCompensation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=hl_DefinedBenefitPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | hl_MetalsInConcentratesAxis=hl_SilverMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | hl_MetalsInConcentratesAxis=hl_GoldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | hl_MetalsInConcentratesAxis=hl_ZincMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | hl_MetalsInConcentratesAxis=hl_LeadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | hl_PensionPlanAxis=hl_UnfundedSupplementalExecutiveRetirementPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | hl_PensionPlanAxis=hl_DefinedBenefitPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |