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Government Inquiries and Other Matters [Member] Represents government inquiries and other matters. Certain Patent Lawsuits [Member] Represents certain patent lawsuits. ICFR Auditor Attestation Flag Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Comprehensive Income (Loss) Note [Text Block] Other comprehensive income (loss): Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] us-gaap_PaymentsOfDebtIssuanceCosts Payment of debt issuance costs Income Tax Jurisdiction [Axis] Income Tax Jurisdiction [Domain] Disaggregation of Revenue [Table Text Block] Domestic Tax Jurisdiction [Member] Disaggregation of Revenue [Table] Foreign Tax Jurisdiction [Member] us-gaap_RepaymentsOfLongTermDebtAndCapitalSecurities Repayments of long-term borrowings and finance lease obligations Accounts Receivable [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] us-gaap_UnrecognizedTaxBenefits Unrecognized tax benefit, beginning of period Unrecognized tax benefit, end of period Accounting Policies [Abstract] Significant Accounting Policies [Text Block] us-gaap_OpenTaxYear Open Tax Year us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations Statute of limitation expirations us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities Settlements Increase in unrecognized tax benefit for positions taken in prior period Increase in unrecognized tax benefit for positions taken in current period Proceeds from long-term borrowings us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense Unrecognized Tax Benefits, Income Tax Penalties Expense us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense Unrecognized Tax Benefits, Interest on Income Taxes Expense Auditor Name Portable Generator Product Liability Case [Member] Represents portable generator product liability case. CPSC Civil Fines [Member] Represents CPSC Civil Fines. Auditor Firm ID Common stock issued under equity incentive plans, net of forfeitures and shares withheld for employee taxes and strike price Equity impact of the value of stock issued under equity incentive plans, net of shares withheld for employee taxes. Auditor Location Excess Purchase Price over Predecessor Basis [Member] The excess purchase price over predecessor basis. Accrued selling expenses The amount of accrued selling expenses. us-gaap_RepaymentsOfShortTermDebt Repayments of short-term borrowings Common stock issued under equity incentive plans, net of forfeitures and shares withheld for employee taxes and strike price (in shares) Number of shares issued under equity incentive plans, net of shares withheld for employee taxes. Current contract liabilities The amount of current contract liabilities. Schedule of Other Accrued Liabilities [Table Text Block] Tabular disclosure of schedule of other accrued liabilities. us-gaap_TaxCreditCarryforwardAmount Tax Credit Carryforward, Amount us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) Weighted average common shares outstanding - diluted: (in shares) Weighted average shares, diluted (in shares) Operating lease liabilities The amount of operating lease liabilities. Accrued legal & professional fees The amount of accrued legal & professional fees. Schedule of Other Accrued Liabilities [Table] Disxlosure of the schedule of other accrued liabilities. Proceeds from short-term borrowings Accrued other The amount of accrued other. Asset Class [Axis] Asset Class [Domain] Statement of Financial Position [Abstract] us-gaap_EarningsPerShareDiluted Net income attributable to Generac Holdings Inc. per common share - diluted: (in dollars per share) Share-based compensation expense (benefit), percent Weighted average common shares outstanding - basic: (in shares) Weighted average shares, basic (in shares) Other, percent us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments us-gaap_EffectiveIncomeTaxRateContinuingOperations Income tax expense, percent Business Combination [Axis] Effect of changes in tax laws or rates enacted in current period, percent us-gaap_EarningsPerShareBasic Net income attributable to Generac Holdings Inc. per common share - basic: (in dollars per share) gnrc_NumberOfMajorCustomers Number of Major Customers Represents number of major customers that accounts for 10 percent or more of the entity's revenues. Business Combination [Domain] Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Changes in valuation allowances, percent gnrc_AmortizationOfFinancingCostsAndDebtDiscountPremium Amortization of Financing Costs and Debt Discount Premium Amount of non-cash expense included in interest expense to issue and amortize debt discount and obtain financing associated with the related debt instruments. Statement of Cash Flows [Abstract] gnrc_DeferredCostsAmortizationExpenseYearTwo Deferred Costs Amortization Expense, Year Two Amount of amortization expense expected to be recognized during the second fiscal year following the latest fiscal year for deferred costs. gnrc_DeferredCostsAmortizationExpenseNextTwelveMonths Deferred Costs Amortization Expense, Next Twelve Months Amount of amortization expense expected to be recognized during the next fiscal year following the latest fiscal year for deferred costs. gnrc_DeferredCostsAmortizationExpenseYearFour Deferred Costs Amortization Expense, Year Four Amount of amortization expense expected to be recognized during the fourth fiscal year following the latest fiscal year for deferred costs. Statement of Stockholders' Equity [Abstract] gnrc_DeferredCostsAmortizationExpenseYearThree Deferred Costs Amortization Expense, Year Three Amount of amortization expense expected to be recognized during the third fiscal year following the latest fiscal year for deferred costs. gnrc_DeferredCostsAmortizationExpenseYearFive Deferred Costs Amortization Expense, Year Five Amount of amortization expense expected to be recognized during the fifth fiscal year following the latest fiscal year for deferred costs. 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Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount Interest component, finance leases Payment of acquisition contingent consideration Value of treasury stock issued for contingent consideration during period. Power Home Solar, LLC Against Generac Power Systems, Inc. [Member] Power Home Solar, LLC Against Generac Power Systems, Inc.. us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths 2026, finance leases us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo 2027, finance leases us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree 2028, finance leases us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour 2029, finance leases Nondeductible U.S. compensation expense, percent gnrc_ProvisionForProductCharges Provision for Product Charges Represents a specific product charge loss provision for a clean energy product customer that filed for bankruptcy, as well as a warranty provision to address certain clean energy product warranty-related matters. us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeIncludingSubsequentAcquisitionPercentage Business Combination, Achieved in Stages, Preacquisition and Acquired Equity Interests in Acquiree, Percentage Share Repurchase Program [Table] Zawaski et al. v. General Power Systems, Inc., et al. [Member] Zawaski et al. v. General Power Systems, Inc., et al. Summary of Cash Taxes Paid [Table Text Block] Tabular disclosure of cash taxes paid. gnrc_DeferredTaxAssetsPrepaidExpenses Prepaid expenses Deferred tax assets related to prepaid expenses. srt_StockRepurchaseProgramAuthorizedAmount1 Share Repurchase Program, Authorized, Amount Allmand [Member] Allmand Finance Leases Share Repurchase Program [Domain] us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsOther Other Credits, percent Changes in unrecognized tax benefits Represents the value of uncertain tax position reserves related to effective income tax rate reconciliation. Share Repurchase Program [Axis] gnrc_IncomeTaxExpenseBenefitBeforeValuationAllowance Total income tax expense Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. State and local income tax, net of federal income tax benefit (1), percent Excluding Extended Warranty [Member] Represents all products excluding extended warranty. Captiva Energy Solutions [Member] Represents information about Captiva Energy Solutions. Foreign Tax Effects, percent The 2019 Equity Incentive Plan [Member] Information related to the 2019 Equity Incentive Plan. Asset Acquisition, Contingent Consideration, Liability, Current Accrued wages and employee benefits gnrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedWagesAndEmployeeBenefits Amount of accrued wages and employee benefits due within one year or within the normal operating cycle, if longer, assumed at the acquisition date. us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch Research and Development Credit, percent Finance Leases (Year) Other us-gaap_IncomeTaxReconciliationOtherAdjustments us-gaap_PaymentsForProceedsFromOtherInvestingActivities Other investing activities Financing activities Debt refinancing costs Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from reserves and accruals, classified as debt refinancing costs. Tax provision at the U.S. federal statutory rate, percent Effect of changes in tax laws or rates enacted in current period Changes in valuation allowances Share-based compensation expense (benefit) gnrc_ContingentConsiderationPayments Payment of contingent consideration (1) Amount of contingent consideration paid during period, including equity issued as payment. Asset Acquisition [Table] Patents and technology, net Represents the carrying amount of finite-lived patents and technology as of balance sheet date. us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet Net assets acquired us-gaap_IncomeTaxReconciliationDeductions Worthless Stock Deduction us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired Payments to Acquire Businesses, Net of Cash Acquired Acquisition of businesses, net of cash acquired Other long-term liabilities us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther Long-term debt us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt us-gaap_PaymentsToAcquireEquityMethodInvestments Contribution to tax equity investment Class of Stock [Axis] Clean Energy Product [Member] Relating to Clean Energy Product. Deferred income taxes us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities Nondeductible U.S. compensation expense Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] us-gaap_PaymentsToAcquireBusinessesGross Payments to Acquire Businesses, Gross Current portion of long-term borrowings and finance lease obligations us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt Other accrued liabilities us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther Domestic [Member] Represents information regarding domestic reportable segment. Accounts payable us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable us-gaap_IncomeTaxReconciliationTaxCreditsOther Other Credits State and local income tax, net of federal income tax benefit (1) Foreign Tax Effects Property and equipment us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment Other assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets International [Member] Represents information regarding international reportable segment. us-gaap_IncomeTaxReconciliationTaxCreditsResearch Research and Development Credit Intangible assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill Tax provision at the U.S. federal statutory rate Schedule Of Intangible Assets [Table Text Block] Tabular disclosure of intangible assets, by major asset class. Proceeds from beneficial interest in securitization transactions Prepaid expenses and other current assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets Accounts receivable us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables Income Tax Disclosure [Text Block] Adjusted EBITDA by reportable segment Represents net income before interest expense, taxes, depreciation and amortization, as further adjusted for other non-cash items Inventories us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory Schedule of Maturities of Long-Term Debt [Table Text Block] Intersegment Sales [Member] Represents intersegment sales. External Net Sales [Member] Represents external net sales. gnrc_BusinessOptimizationExpense Business optimization and other charges (5) Represents charges relating to business optimization and restructuring costs. Extended Warranties [Member] Relating to extended warranties. gnrc_Other Other Represents other non-cash items that are not categorized separately. gnrc_LossOnModificationOfDebt Loss on Extinguishment of Debt Loss on refinancing of debt Represents information about loss on modification of debt. Accumulated Other Comprehensive Income (Loss) [Table] ecd_TrdArrExpirationDate Trading Arrangement Expiration Date gnrc_TransactionCostsAndCredityFaciltyFees Transaction costs and credit facility fees (4) Represents transaction costs incurred directly in connection with any investment, as defined in our credit agreement; equity issuance, debt issuance or refinancing; together with certain fees relating to our senior secured credit facilities. us-gaap_BusinessCombinationConsiderationTransferred1 Business Combination, Consideration Transferred gnrc_NoncashWritedownAndOtherAdjustments Non-cash write-down and other adjustments (2) Represents information about non-cash write-down and other adjustments. Includes gains/losses on disposal of assets, unrealized mark-to-market adjustments on commodity contracts, and certain foreign currency and purchase accounting related adjustments. Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred Business Combination, Consideration Transferred, Liabilities Incurred Share-Based Payment Arrangement, Option, Activity [Table Text Block] us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired Business Combination, Voting Equity Interest Acquired, Percentage Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] us-gaap_GoodwillAndIntangibleAssetImpairment Goodwill and Intangible Asset Impairment gnrc_PerformanceShareAwardPercentage Performance Share Award, Percentage The percentage of the target performance share award. gnrc_CovenantMinimumInterestCoverageRatio Covenant Minimum Interest Coverage Ratio The minimum interest coverage ratio required under the covenant. us-gaap_PaymentsToAcquireInvestments Payments to Acquire Investments us-gaap_PaymentsToAcquireLongtermInvestments Purchase of long-term investments Proceeds from sale of long-term investments Goodwill, gross us-gaap_GoodwillImpairedAccumulatedImpairmentLoss Accumulated impairment Goodwill and Intangible Assets Disclosure [Text Block] Schedule of Goodwill [Table Text Block] Goodwill [Table] gnrc_DebtInstrumentSOFRFloor Debt Instrument, SOFR Floor SOFR floor rate on debt instrument. Tranche A Term Loan Facility and Revolving Credit Facility [Member] Represent the Tranche A Term Loan Facility and Revolving Credit Facility. Revolving Credit Facility [Member] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Credit Facility [Axis] Proceeds from sale of property and equipment Credit Facility [Domain] Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block] Trade Names [Member] us-gaap_IncrementalCommonSharesAttributableToContingentlyIssuableShares Dilutive effect of contingently issued shares (in shares) Capital expenditures Expenditures for property and equipment us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements Dilutive effect of stock compensation awards (1) (in shares) Income taxes Total income taxes paid, net Noncompete Agreements [Member] Tranche A Term Loan Facility [Member] Borrowing supported by a written promise to pay an obligation. us-gaap_EquitySecuritiesFvNiGainLoss Equity Securities, FV-NI, Gain (Loss) Supplemental disclosure of cash flow information Tranche B Term Loan Facility [Member] Borrowing supported by a written promise to pay an obligation. gnrc_TreasuryStockSharesAcquiredInSettlementOfRestrictedStockAwards Net share settlement of restricted stock awards (in shares) Number of shares that have been repurchased during the period and are being held in treasury in settlement of restricted stock award. gnrc_TreasuryStockValueAcquiredInSettlementOfRestrictedStockAwardCostMethod Net share settlement of restricted stock awards Equity impact of the cost of common and preferred stock that were repurchased during the period in settlement of restricted stock award. Recorded using the cost method. Other Long-term Liabilities [Member] Represents other long-term liabilities. Customer Lists [Member] No Customer [Member] Represents no customer. Computer Software, Intangible Asset [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Business Combination, Contingent Consideration [Table] Effect of cross-border tax laws Present value interest accretion The amount of increase due to present value interest accretion in contingent consideration arrangements from business combinations. Business Combination, Contingent Consideration [Table Text Block] Effective Income Tax Rate Reconciliation [Table] Effect of cross-border tax laws, percent gnrc_DeferredIncomeTaxExpenseBenefitBeforeAdjustmentOfValuationAllowance Total deferred tax expense (benefit) The component of income tax expense for the period representing the increase (decrease) in the entity's deferred tax assets and liabilities pertaining to continuing operations before adjustment of change in valuation allowance. gnrc_TaxCreditCarryforwardStateManufacturing Tax Credit Carryforward State Manufacturing The amount of the state manufacturing tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. us-gaap_NetIncomeLoss Net income attributable to Generac Holdings Inc. Net income attributable to Generac Holdings Inc. gnrc_DefinedContributionPlanPercentageOfEligibleCompensation Defined Contribution Plan Percentage of Eligible Compensation Percentage of eligible compensation of employees under defined contribution plan. gnrc_EmployerContributionUnderMedicalAndDentalPlan Employer Contribution under Medical and Dental Plan Contribution made under medical and dental plan made by the employer. Restricted Stock [Member] Settled Dispute With a Supplier for a Discontinued Product [Member] Relating to a settled dispute with a supplier for a discontinued product. Performance Shares [Member] Share-Based Payment Arrangement, Option [Member] gnrc_AccrualForLegalSettlementsToBePaidInCash Accrual for Legal Settlements to be Paid in Cash Represents the amount reserved for legal settlements to be paid in cash. Antidilutive Security, Excluded EPS Calculation [Table] Foreign currency translation rate changes Previous Year [Member] Relating to previous year. Purchase accounting adjustments us-gaap_GoodwillAcquiredDuringPeriod Acquisitions of businesses, net Lessee, Operating Leases and Finance Leases [Text Block] The entire disclosure for operating leases and finance leases of lessee. Business Combination [Text Block] Long-Term Debt, Type [Axis] Long-Term Debt, Type [Domain] Expected annual dividend per share (in dollars per share) The estimated amount of dividends per share to be paid to holders of the underlying shares (expected dividends) over the option's term. Investing activities Valuation and Qualifying Accounts [Table Text Block] A tabular disclosure of allowance and reserve accounts including their beginning and ending balances, as well as a reconciliation by type of activity during the period. Alternatively, disclosure of the required information may be within the footnotes to the financial statements or a supplemental schedule to the financial statements. us-gaap_ExtinguishmentOfDebtAmount Extinguishment of Debt, Amount Earnings Per Share [Text Block] Intersegment Eliminations [Member] Customer lists, net Carrying amount, net of accumulated amortization, as of the balance sheet date of an asset having a finite beneficial life acquired in a business combination or other transaction representing a favorable existing relationship with customers. us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities Accrued wages and employee benefits CANADA us-gaap_IncreaseDecreaseInOtherAccruedLiabilities Other accrued liabilities Tradenames, net The net carrying amount as of the balance sheet date of indefinite-lived and finite-lived tradenames on the statement of financial position representing the rights acquired through registration of a trade name to gain or protect exclusive use thereof. Unrealized gain (loss) on interest rate swaps, tax SEC Schedule, 12-09, Reserve, Inventory [Member] us-gaap_IncreaseDecreaseInAccountsPayable Accounts payable Depreciation and Amortization The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. Amount includes additional accelerated depreciation recognized in the current period. gnrc_ExcessPurchasePriceOverPredecessorBasis Excess purchase price over predecessor basis The element that represents the excess purchase price over predecessor basis. us-gaap_IncomeTaxPaidFederalAfterRefundReceived U.S Federal Other Accrued Liabilities [Member] Related to other accrued liabilities. Operating Lease and Other Assets [Member] Related to operating lease and other assets. us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived Total U.S. State and Local Operating Lease and Other Long-term Liabilities [Member] Related to operating lease and other long-term liabilities. us-gaap_IncomeTaxPaidForeignAfterRefundReceived Foreign taxes us-gaap_InterestExpenseNonoperating Interest expense UNITED KINGDOM SEC Schedule, 12-09, Allowance, Credit Loss [Member] us-gaap_AllocatedShareBasedCompensationExpense Share-Based Payment Arrangement, Expense gnrc_NumberOfNewContractsEntered Number of New Contracts Entered Number of new contracts entered into during the period mentioned. gnrc_DerivativeAssetsLiabilitiesNetFairValueOfDerivativeContractsExcludingImpactOfCreditRisk Derivative Assets (Liabilities), Net Fair Value of Derivative Contracts, Excluding Impact of Credit Risk Represents the fair value of derivative contracts excluding impact of credit risk. Schedule Of Derivative Assets (Liabilities) at Fair Value [Table Text Block] Tabular disclosure of derivative assets and liabilities at fair value. us-gaap_ComprehensiveIncomeNetOfTax Comprehensive income attributable to Generac Holdings Inc. us-gaap_TreasuryStockSharesAcquired Treasury Stock, Shares, Acquired (in shares) Stock repurchases (in shares) us-gaap_SharesOutstanding Balance (in shares) Balance (in shares) us-gaap_JointVentureFormationFairValueOfJointVenture Joint Venture Formation, Fair Value of Joint Venture us-gaap_IncreaseDecreaseInOtherOperatingAssets Other assets us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 Debt Instrument, Basis Spread on Variable Rate us-gaap_DebtInstrumentInterestRateStatedPercentage Debt Instrument, Interest Rate, Stated Percentage us-gaap_LeaseCost Total lease cost us-gaap_DebtInstrumentInterestRateEffectivePercentage Debt Instrument, Interest Rate, Effective Percentage us-gaap_DebtInstrumentFairValue Debt Instrument, Fair Value Disclosure Operating Leases Operating lease cost Lease, Cost [Table Text Block] Finance leases Operating leases Operating Leases (Year) us-gaap_DebtInstrumentFaceAmount Debt Instrument, Face Amount us-gaap_DividendsCommonStockCash Cash dividends paid to noncontrolling interest of subsidiary us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Debt Instrument [Axis] Debt Instrument, Name [Domain] Variable Rate [Domain] Schedule of Long-Term Debt Instruments [Table Text Block] Variable Rate [Axis] us-gaap_CapitalizedContractCostAmortization Capitalized Contract Cost, Amortization Residential Power Products [Member] Represents products and services related to residential power. us-gaap_IncreaseDecreaseInAccountsReceivable Accounts receivable Share-based compensation Contingent Consideration Liability [Member] Represents contingent consideration liabilities. Commercial and Industrial Power Products [Member] Represents products and services related to commercial and industrial power. Liability Class [Axis] Fair Value by Liability Class [Domain] Other Products and Services [Member] Represents information pertaining to products and services not separately disclosed. us-gaap_TreasuryStockValueAcquiredCostMethod Treasury Stock, Value, Acquired, Cost Method Stock repurchases Dies and Tools [Member] Tangible personal property used to produce goods and services. us-gaap_TreasuryStockCommonValue Treasury stock, at cost, 15,373,990 and 14,173,697 shares as of December 31, 2025 and 2024, respectively Amortization of deferred revenue contracts Represents the aggregate decrease in the liability for accruals related to extended product warranties issued during the reporting period, due to amortization of deferred revenue. Product Warranty Obligations Included In Consolidated Balance Sheet [Table Text Block] Product warranty obligations included in consolidated balance sheet. us-gaap_IncreaseDecreaseInInventories Inventories gnrc_UncommittedIncrementalTermLoanFacility Uncommitted Incremental Term Loan Facility Refers to uncommitted incremental term loan facility after amendment. us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity Line of Credit Facility, Remaining Borrowing Capacity us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised Exercised, number of options (in shares) us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity Secured Overnight Financing Rate (SOFR) [Member] Granted, number of options (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod Forfeited, number of options (in shares) Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Acquisition of REFUstor [Member] Represents information regarding the acquisition of REFUstor, headquartered in Pfullingen, Germany. REFUstor is a developer and supplier of battery storage hardware products, advanced software, and platform services for the C&I energy storage market. Wolverine, Ageto, C&I BESS, and Huntington [Member] Identification of the acquiree in a material business combination (or series of individually immaterial business combinations), which may include the name or other type of identification of the acquiree. gnrc_AmountFinancedByDealers Amount Financed by Dealers Amount financed by dealers to purchase goods from the entity. Line of Credit Facility [Table] Other segment items (1) Fair value of Contingent Consideration in a Business Combination [Policy Text Block] Disclosure for the accounting policy for the fair value of contingent consideration in a business combination. us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and stockholders’ equity UNITED STATES us-gaap_ShortTermDebtWeightedAverageInterestRate Short-Term Debt, Weighted Average Interest Rate, at Point in Time Retained earnings Accumulated other comprehensive income (loss) Debt Disclosure [Text Block] The 2024 Acquisitions [Member] The 2024 business acquisitions. Net changes in operating assets and liabilities: gnrc_DeferredCompensationArrangementWithIndividualSharesGranted Deferred Compensation Arrangement with Individual, Shares Granted (in shares) The number of shares granted in a deferred compensation arrangement with an individual. Class Action Lawsuits [Member] The class action lawsuits. Operating lease liabilities - noncurrent Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Total operating lease liabilities Present value of minimum lease payments, operating leases gnrc_JointVentureFormationFundedByNoncontrollingInterestPercent Joint Venture Formation, Funded by Non-controlling Interest, Percent The percent value of the amount of the joint venture funded by the other party. gnrc_TemporaryEquityContributionsFromNoncontrollingInterestHolders Contribution received from noncontrolling interest holder The amount of contributions received from non-controlling interest holders, attributable to temporary equity. Operating lease liabilities - current Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Less: current portion of finance lease obligation Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] E.A. Juffali and Brothers [Member] E.A. Juffali and Brothers Finance lease liabilities - noncurrent Generac Juffali Generators WLL [Member] Generac Juffali Generators WLL Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Operating lease ROU assets Multi-district Class Action Lawsuit [Member] Multi-district Class Action Lawsuit Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Total minimum lease payments, operating leases us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount Interest component, operating leases Finance lease obligation Present value of minimum lease payments, finance leases Financing cash flows - finance leases us-gaap_DeferredIncomeTaxExpenseBenefit Deferred income tax expense (benefit) us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree 2028, operating leases Ageto Acquisition [Member] Ageto Acquisition us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour 2029, operating leases us-gaap_FinanceLeaseRightOfUseAsset Finance Lease, Right-of-Use Asset, after Accumulated Amortization Finance lease ROU assets, net 2030, operating leases us-gaap_UnrealizedGainLossOnInvestments Change in fair value of investments (7) Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive After 2030, operating leases Net Investment in Lease, before Allowance for Credit Loss New Revolving Facility [Member] New Revolving Facility us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths 2026, operating leases New Tranche A Term Loan Facility and Term Loan B Facility [Member] New Tranche A Term Loan Facility and Term Loan B Facility us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo 2027, operating leases gnrc_DebtInstrumentInterestRateReduction Debt Instrument, Interest Rate, Reduction The reduction in the contractual interest rate for funds borrowed, under the debt agreement. Equity Incentive Plan (Plan) [Member] Represents the equity incentive plan (Plan). us-gaap_ShareBasedCompensation Share-based compensation expense Non-cash share-based compensation expense (3) Daniel Haak Lawsuit [Member] Daniel Haak Lawsuit New Credit Facility [Member] New Credit Facility Amortization of deferred financing costs and original issue discount New Tranche A Term Loan [Member] New Tranche A Term Loan Depreciation and finance lease amortization Depreciation us-gaap_DepreciationDepletionAndAmortization Depreciation and amortization us-gaap_UnrealizedGainLossOnDerivatives Unrealized Gain (Loss) on Derivatives gnrc_BusinessAcquisitionNoncontrollingInterestTermOfPutOption Business Acquisition, Noncontrolling Interest, Term of Put Option (Year) The term of a put option available to the noncontrolling interest of a business acquired by the reporting entity. Treasury stock, shares (in shares) Balance (in shares) Balance (in shares) Common stock, par value $0.01, 500,000,000 shares authorized, 74,050,753 and 73,785,631 shares issued as of December 31, 2025 and 2024, respectively Adjustments to reconcile net income to net cash provided by operating activities: gnrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsIncludingGoodwill Total assets acquired Represents the total assets acquired from a business combination which includes identifiable assets acquired and liabilities assumed assets, including goodwill. Common stock, shares authorized (in shares) Common stock, shares issued (in shares) Redeemable Noncontrolling Interest [Text Block] Entire disclosure for redeemable noncontrolling interest. Common stock, par value (in dollars per share) gnrc_ExtendedWarrantyTerm Extended Warranty Term (Year) Expiration period of the extended warranty. Lessee, Lease, Description [Table] Statistical Measurement [Domain] Operating cash flows - operating leases Maximum [Member] Minimum [Member] Ownership [Domain] Product and Service [Axis] Product and Service [Domain] Statistical Measurement [Axis] Operating cash flows - finance leases Litigation Case [Axis] Litigation Case [Domain] Ownership [Axis] Interest Savings Plan 401(k) [Member] Represents the companies defined-contribution 401(k) savings plan. Geographical [Axis] Geographical [Domain] Property, Plant and Equipment [Table Text Block] Fair Value, Inputs, Level 3 [Member] Fair Value Hierarchy and NAV [Domain] Customer [Axis] Customer [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value Hierarchy and NAV [Axis] us-gaap_ExtendedProductWarrantyAccrual Total Balance at beginning of period Balance at end of period Patents and Technology [Member] Represents finite-lived intangible assets classified as patents and technology. us-gaap_ExtendedProductWarrantyAccrualCurrent Current portion - other accrued liabilities us-gaap_ExtendedProductWarrantyAccrualNoncurrent Long-term portion - Deferred revenue Noncontrolling interests Operating activities Revenue [Policy Text Block] Deferred revenue contracts issued Statement [Line Items] Current portion - accrued product warranty Long-term portion - other long-term liabilities us-gaap_StandardProductWarrantyAccrual Total Balance at beginning of period Balance at end of period us-gaap_StandardProductWarrantyAccrualPayments Payments Additional paid-in capital Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Provision for warranty issued AOCI Attributable to Parent [Member] Changes in estimates for pre-existing warranties Schedule of Product Warranty Liability [Table Text Block] Stockholders’ equity: Product Warranty Liability [Table] Product Warranty Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Redeemable noncontrolling interest us-gaap_Liabilities Total liabilities gnrc_CovenantMaximumTotalLeverageRatio Covenant Maximum Total Leverage Ratio The maximum financial condition covenant applicable to Tranche A Term Loan Facility and Revolving Facility only. us-gaap_ContractWithCustomerLiabilityRevenueRecognized Contract with Customer, Liability, Revenue Recognized Prepaid expenses and other assets Counterparty Name [Axis] Counterparty Name [Domain] Deferred income taxes us-gaap_DeferredIncomeTaxLiabilitiesNet Deferred Income Tax Liabilities, Net Consolidation Items [Domain] us-gaap_ContractWithCustomerLiability Balance Balance Consolidation Items [Axis] Operating Lease, Liability, Noncurrent And Other Long-term Liabilities Present value of lessee's discounted obligation for lease payments from operating lease, and other liabilities classified as noncurrent. Operating Lease, Right-of-Use Asset and Other Assets, Noncurrent Amount of lessee's right to use underlying asset under operating lease and other assets after one year or beyond the normal operating cycle, if longer. Schedule of Components of Lease Assets and Liabilities [Table Text Block] Tabular disclosure of components of lease assets and liabilities. gnrc_LesseeOperatingLeaseAndFinanceLeaseRemainingTermOfContract Lessee, Operating Lease and Finance Lease, Remaining Term of Contract (Year) Remaining term of lessee's operating lease and finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Schedule of Leases Cash Flow Information [Table Text Block] Tabular disclosure of leases related to cash flow information. gnrc_FinanceLeaseRightOfUseAssetAccumulatedDepreciation Accumulated depreciation - finance lease ROU assets Amount of accumulated depreciation for finance lease right of use assets. Finance lease ROU assets, gross Gross amount of lessee's right to use underlying asset under finance lease. Operating and Finance Lease, Liability, Maturity [Table Text Block] Tabular disclosure of undiscounted cash flows of operating and finance lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to operating and finance lease liability recognized in statement of financial position. Restricted Stock and Performance Shares [Member] Represents information about restricted stock and performance shares. Lease, Term and Discount Rate [Table Text Block] Tabular disclosure of term and discount rate of lease. Noncontrolling Interest [Member] Retained Earnings [Member] Treasury Stock, Common [Member] us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1 Share Repurchase Program, Remaining Authorized, Amount us-gaap_StockRepurchaseProgramPeriodInForce1 Share Repurchase Program, Period in Force (Year) Additional Paid-in Capital [Member] Parent [Member] Common Stock [Member] Other us-gaap_OtherBorrowings Equity Components [Axis] us-gaap_DebtAndCapitalLeaseObligations Total Equity Component [Domain] us-gaap_LongTermDebt Long-Term Debt Prepaid Expenses and Other Current Assets [Member] us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) Class of Warrant or Right [Axis] Class of Warrant or Right [Domain] us-gaap_LineOfCredit Long-Term Line of Credit us-gaap_DeferredFinanceCostsNet Debt Issuance Costs, Net Vehicles [Member] us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Original issue discount and deferred financing costs gnrc_ExcessTaxBenefitsFromEquityAwards Excess tax benefits from equity awards The value of excess tax benefits from equity awards. Office Equipment [Member] Document Annual Report Machinery and Equipment [Member] Statement of Financial Position Location, Balance [Axis] Statement of Financial Position Location, Balance [Domain] Entity Incorporation, State or Country Code Long-term borrowings Long-Term Debt, Gross Document Transition Report Document Financial Statement Error Correction [Flag] Short-term borrowings Short-Term Debt Entity Interactive Data Current Security Exchange Name Title of 12(b) Security Long-Term Debt and Lease Obligation Total long-term borrowings and finance lease obligations Reserves established for acquisitions us-gaap_ValuationAllowancesAndReservesBalance Beginning Ending Additions charged to earnings Charges to reserve, net Collaborative Arrangement and Arrangement Other than Collaborative [Axis] us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners Subsidiary, Ownership Percentage, Noncontrolling Owner Redemption value adjustment Redemption value adjustment Redemption value adjustment Segments [Axis] Segments [Domain] us-gaap_RedeemableNoncontrollingInterestEquityFairValue Redeemable Noncontrolling Interest, Equity, Fair Value Redeemable Noncontrolling Interest [Table Text Block] Non-US [Member] Noncontrolling Interest [Table] SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Statement [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] us-gaap_MinorityInterestOwnershipPercentageByParent Subsidiary, Ownership Percentage, Parent Income Statement [Abstract] 2028 2029 2030 us-gaap_BusinessCombinationContingentConsiderationLiability Business Combination, Contingent Consideration, Liability Beginning balance Beginning balance 2026 2027 Accounting Standards Update and Change in Accounting Principle [Table] us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent Business Combination, Contingent Consideration, Liability, Noncurrent Liabilities, Noncurrent Fair Value of Derivatives Revolving Facility [Member] The revolving credit facility. Deferred revenue us-gaap_StockholdersEquity Stockholders’ equity attributable to Generac Holdings Inc. us-gaap_LongTermDebtNoncurrent Total Net unrealized loss on derivatives Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Interest Rate Swap [Member] Operating Segments [Member]