| | | | | | | | | | | | | | | | | | | | | |
<?xml version="1.0" encoding="windows-1252"?> |
<FilingSummary> |
| <Version> 3.20.4 </Version> |
| <ProcessingTime/> |
| <ReportFormat> html </ReportFormat> |
| <ContextCount> 349 </ContextCount> |
| <ElementCount> 567 </ElementCount> |
| <EntityCount> 1 </EntityCount> |
| <FootnotesReported> true </FootnotesReported> |
| <SegmentCount> 88 </SegmentCount> |
| <ScenarioCount> 0 </ScenarioCount> |
| <TuplesReported> false </TuplesReported> |
| <UnitCount> 7 </UnitCount> |
| <MyReports> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R1.htm </HtmlFileName> |
| | | <LongName> 000 - Document - Document And Entity Information </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-document-and-entity-information </Role> |
| | | <ShortName> Document And Entity Information </ShortName> |
| | | <MenuCategory> Cover </MenuCategory> |
| | | <Position> 1 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R2.htm </HtmlFileName> |
| | | <LongName> 001 - Statement - Consolidated Balance Sheets </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-consolidated-balance-sheets </Role> |
| | | <ShortName> Consolidated Balance Sheets </ShortName> |
| | | <MenuCategory> Statements </MenuCategory> |
| | | <Position> 2 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R3.htm </HtmlFileName> |
| | | <LongName> 002 - Statement - Consolidated Balance Sheets (Parentheticals) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-consolidated-balance-sheets-parentheticals </Role> |
| | | <ShortName> Consolidated Balance Sheets (Parentheticals) </ShortName> |
| | | <MenuCategory> Statements </MenuCategory> |
| | | <Position> 3 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R4.htm </HtmlFileName> |
| | | <LongName> 003 - Statement - Consolidated Statements of Comprehensive Income </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-consolidated-statements-of-comprehensive-income- </Role> |
| | | <ShortName> Consolidated Statements of Comprehensive Income </ShortName> |
| | | <MenuCategory> Statements </MenuCategory> |
| | | <Position> 4 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R5.htm </HtmlFileName> |
| | | <LongName> 004 - Statement - Consolidated Statements of Stockholders' Equity </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-consolidated-statements-of-stockholders-equity </Role> |
| | | <ShortName> Consolidated Statements of Stockholders' Equity </ShortName> |
| | | <MenuCategory> Statements </MenuCategory> |
| | | <Position> 5 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R6.htm </HtmlFileName> |
| | | <LongName> 005 - Statement - Consolidated Statements of Stockholders' Equity (Parentheticals) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-consolidated-statements-of-stockholders-equity-parentheticals </Role> |
| | | <ShortName> Consolidated Statements of Stockholders' Equity (Parentheticals) </ShortName> |
| | | <MenuCategory> Statements </MenuCategory> |
| | | <Position> 6 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R7.htm </HtmlFileName> |
| | | <LongName> 006 - Statement - Consolidated Statements of Cash Flows </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-consolidated-statements-of-cash-flows </Role> |
| | | <ShortName> Consolidated Statements of Cash Flows </ShortName> |
| | | <MenuCategory> Statements </MenuCategory> |
| | | <Position> 7 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R8.htm </HtmlFileName> |
| | | <LongName> 007 - Disclosure - Note 1 - Description of Business </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-1-description-of-business </Role> |
| | | <ShortName> Note 1 - Description of Business </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 8 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R9.htm </HtmlFileName> |
| | | <LongName> 008 - Disclosure - Note 2 - Summary of Accounting Policies </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies </Role> |
| | | <ShortName> Note 2 - Summary of Accounting Policies </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 9 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R10.htm </HtmlFileName> |
| | | <LongName> 009 - Disclosure - Note 3 - Acquisitions </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-3-acquisitions </Role> |
| | | <ShortName> Note 3 - Acquisitions </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 10 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R11.htm </HtmlFileName> |
| | | <LongName> 010 - Disclosure - Note 4 - Redeemable Noncontrolling Interest </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-4-redeemable-noncontrolling-interest </Role> |
| | | <ShortName> Note 4 - Redeemable Noncontrolling Interest </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 11 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R12.htm </HtmlFileName> |
| | | <LongName> 011 - Disclosure - Note 5 - Derivative Instruments and Hedging Activities </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-5-derivative-instruments-and-hedging-activities </Role> |
| | | <ShortName> Note 5 - Derivative Instruments and Hedging Activities </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 12 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R13.htm </HtmlFileName> |
| | | <LongName> 012 - Disclosure - Note 6 - Accumulated Other Comprehensive Loss </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss </Role> |
| | | <ShortName> Note 6 - Accumulated Other Comprehensive Loss </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 13 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R14.htm </HtmlFileName> |
| | | <LongName> 013 - Disclosure - Note 7 - Segment Reporting </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-7-segment-reporting </Role> |
| | | <ShortName> Note 7 - Segment Reporting </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 14 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R15.htm </HtmlFileName> |
| | | <LongName> 014 - Disclosure - Note 8 - Balance Sheet Details </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details </Role> |
| | | <ShortName> Note 8 - Balance Sheet Details </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 15 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R16.htm </HtmlFileName> |
| | | <LongName> 015 - Disclosure - Note 9 - Goodwill and Intangible Assets </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets </Role> |
| | | <ShortName> Note 9 - Goodwill and Intangible Assets </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 16 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R17.htm </HtmlFileName> |
| | | <LongName> 016 - Disclosure - Note 10 - Leases </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases- </Role> |
| | | <ShortName> Note 10 - Leases </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 17 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R18.htm </HtmlFileName> |
| | | <LongName> 017 - Disclosure - Note 11 - Product Warranty Obligations </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 18 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R19.htm </HtmlFileName> |
| | | <LongName> 018 - Disclosure - Note 12 - Credit Agreements </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-12-credit-agreements </Role> |
| | | <ShortName> Note 12 - Credit Agreements </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 19 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R20.htm </HtmlFileName> |
| | | <LongName> 019 - Disclosure - Note 13 - Stock Repurchase Programs </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-13-stock-repurchase-programs </Role> |
| | | <ShortName> Note 13 - Stock Repurchase Programs </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 20 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R21.htm </HtmlFileName> |
| | | <LongName> 020 - Disclosure - Note 14 - Earnings Per Share </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-14-earnings-per-share </Role> |
| | | <ShortName> Note 14 - Earnings Per Share </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 21 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R22.htm </HtmlFileName> |
| | | <LongName> 021 - Disclosure - Note 15 - Income Taxes </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes </Role> |
| | | <ShortName> Note 15 - Income Taxes </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 22 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R23.htm </HtmlFileName> |
| | | <LongName> 022 - Disclosure - Note 16 - Benefit Plans </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-16-benefit-plans </Role> |
| | | <ShortName> Note 16 - Benefit Plans </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 23 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R24.htm </HtmlFileName> |
| | | <LongName> 023 - Disclosure - Note 17 - Share Plans </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-17-share-plans </Role> |
| | | <ShortName> Note 17 - Share Plans </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 24 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R25.htm </HtmlFileName> |
| | | <LongName> 024 - Disclosure - Note 18 - Commitments and Contingencies </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-18-commitments-and-contingencies </Role> |
| | | <ShortName> Note 18 - Commitments and Contingencies </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 25 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R26.htm </HtmlFileName> |
| | | <LongName> 025 - Disclosure - Note 19 - Quarterly Financial Information (Unaudited) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-19-quarterly-financial-information-unaudited </Role> |
| | | <ShortName> Note 19 - Quarterly Financial Information (Unaudited) </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 26 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R27.htm </HtmlFileName> |
| | | <LongName> 026 - Disclosure - Note 20 - Valuation and Qualifying Accounts </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-20-valuation-and-qualifying-accounts </Role> |
| | | <ShortName> Note 20 - Valuation and Qualifying Accounts </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 27 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R28.htm </HtmlFileName> |
| | | <LongName> 027 - Disclosure - Note 21 - Subsequent Events </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-21-subsequent-events </Role> |
| | | <ShortName> Note 21 - Subsequent Events </ShortName> |
| | | <MenuCategory> Notes </MenuCategory> |
| | | <Position> 28 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R29.htm </HtmlFileName> |
| | | <LongName> 028 - Disclosure - Significant Accounting Policies (Policies) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-significant-accounting-policies-policies </Role> |
| | | <ShortName> Significant Accounting Policies (Policies) </ShortName> |
| | | <MenuCategory> Policies </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies </ParentRole> |
| | | <Position> 29 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R30.htm </HtmlFileName> |
| | | <LongName> 029 - Disclosure - Note 2 - Summary of Accounting Policies (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies-tables </Role> |
| | | <ShortName> Note 2 - Summary of Accounting Policies (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies </ParentRole> |
| | | <Position> 30 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R31.htm </HtmlFileName> |
| | | <LongName> 030 - Disclosure - Note 3 - Acquisitions (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-3-acquisitions-tables </Role> |
| | | <ShortName> Note 3 - Acquisitions (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-3-acquisitions </ParentRole> |
| | | <Position> 31 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R32.htm </HtmlFileName> |
| | | <LongName> 031 - Disclosure - Note 4 - Redeemable Noncontrolling Interest (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-4-redeemable-noncontrolling-interest-tables </Role> |
| | | <ShortName> Note 4 - Redeemable Noncontrolling Interest (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-4-redeemable-noncontrolling-interest </ParentRole> |
| | | <Position> 32 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R33.htm </HtmlFileName> |
| | | <LongName> 032 - Disclosure - Note 5 - Derivative Instruments and Hedging Activities (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-5-derivative-instruments-and-hedging-activities-tables </Role> |
| | | <ShortName> Note 5 - Derivative Instruments and Hedging Activities (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-5-derivative-instruments-and-hedging-activities </ParentRole> |
| | | <Position> 33 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R34.htm </HtmlFileName> |
| | | <LongName> 033 - Disclosure - Note 6 - Accumulated Other Comprehensive Loss (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss-tables </Role> |
| | | <ShortName> Note 6 - Accumulated Other Comprehensive Loss (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss </ParentRole> |
| | | <Position> 34 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R35.htm </HtmlFileName> |
| | | <LongName> 034 - Disclosure - Note 7 - Segment Reporting (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-7-segment-reporting-tables </Role> |
| | | <ShortName> Note 7 - Segment Reporting (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-7-segment-reporting </ParentRole> |
| | | <Position> 35 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R36.htm </HtmlFileName> |
| | | <LongName> 035 - Disclosure - Note 8 - Balance Sheet Details (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details-tables </Role> |
| | | <ShortName> Note 8 - Balance Sheet Details (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details </ParentRole> |
| | | <Position> 36 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R37.htm </HtmlFileName> |
| | | <LongName> 036 - Disclosure - Note 9 - Goodwill and Intangible Assets (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets-tables </Role> |
| | | <ShortName> Note 9 - Goodwill and Intangible Assets (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets </ParentRole> |
| | | <Position> 37 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R38.htm </HtmlFileName> |
| | | <LongName> 037 - Disclosure - Note 10 - Leases (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-tables </Role> |
| | | <ShortName> Note 10 - Leases (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-10-leases- </ParentRole> |
| | | <Position> 38 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R39.htm </HtmlFileName> |
| | | <LongName> 038 - Disclosure - Note 11 - Product Warranty Obligations (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-tables </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations </ParentRole> |
| | | <Position> 39 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R40.htm </HtmlFileName> |
| | | <LongName> 039 - Disclosure - Note 12 - Credit Agreements (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-12-credit-agreements-tables </Role> |
| | | <ShortName> Note 12 - Credit Agreements (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-12-credit-agreements </ParentRole> |
| | | <Position> 40 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R41.htm </HtmlFileName> |
| | | <LongName> 040 - Disclosure - Note 14 - Earnings Per Share (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-14-earnings-per-share-tables </Role> |
| | | <ShortName> Note 14 - Earnings Per Share (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-14-earnings-per-share </ParentRole> |
| | | <Position> 41 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R42.htm </HtmlFileName> |
| | | <LongName> 041 - Disclosure - Note 15 - Income Taxes (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes-tables </Role> |
| | | <ShortName> Note 15 - Income Taxes (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-15-income-taxes </ParentRole> |
| | | <Position> 42 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R43.htm </HtmlFileName> |
| | | <LongName> 042 - Disclosure - Note 17 - Share Plans (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-17-share-plans-tables </Role> |
| | | <ShortName> Note 17 - Share Plans (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-17-share-plans </ParentRole> |
| | | <Position> 43 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R44.htm </HtmlFileName> |
| | | <LongName> 043 - Disclosure - Note 19 - Quarterly Financial Information (Unaudited) (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-19-quarterly-financial-information-unaudited-tables </Role> |
| | | <ShortName> Note 19 - Quarterly Financial Information (Unaudited) (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-19-quarterly-financial-information-unaudited </ParentRole> |
| | | <Position> 44 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R45.htm </HtmlFileName> |
| | | <LongName> 044 - Disclosure - Note 20 - Valuation and Qualifying Accounts (Tables) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-20-valuation-and-qualifying-accounts-tables </Role> |
| | | <ShortName> Note 20 - Valuation and Qualifying Accounts (Tables) </ShortName> |
| | | <MenuCategory> Tables </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-20-valuation-and-qualifying-accounts </ParentRole> |
| | | <Position> 45 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R46.htm </HtmlFileName> |
| | | <LongName> 045 - Disclosure - Note 2 - Summary of Accounting Policies (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies-details-textual </Role> |
| | | <ShortName> Note 2 - Summary of Accounting Policies (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies-tables </ParentRole> |
| | | <Position> 46 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R47.htm </HtmlFileName> |
| | | <LongName> 046 - Disclosure - Note 2 - Summary of Accounting Policies - Summary of Allowance for Doubtful Accounts (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies-summary-of-allowance-for-doubtful-accounts-details </Role> |
| | | <ShortName> Note 2 - Summary of Accounting Policies - Summary of Allowance for Doubtful Accounts (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 47 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R48.htm </HtmlFileName> |
| | | <LongName> 047 - Disclosure - Note 2 - Summary of Accounting Policies - Property and Equipment Estimated Useful Lives (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-2-summary-of-accounting-policies-property-and-equipment-estimated-useful-lives-details </Role> |
| | | <ShortName> Note 2 - Summary of Accounting Policies - Property and Equipment Estimated Useful Lives (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 48 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R49.htm </HtmlFileName> |
| | | <LongName> 048 - Disclosure - Note 3 - Acquisitions (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-3-acquisitions-details-textual </Role> |
| | | <ShortName> Note 3 - Acquisitions (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-3-acquisitions-tables </ParentRole> |
| | | <Position> 49 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R50.htm </HtmlFileName> |
| | | <LongName> 049 - Disclosure - Note 3 - Acquisitions - Preliminary Price Allocation (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-3-acquisitions-preliminary-price-allocation-details </Role> |
| | | <ShortName> Note 3 - Acquisitions - Preliminary Price Allocation (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 50 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R51.htm </HtmlFileName> |
| | | <LongName> 050 - Disclosure - Note 3 - Acquisitions - Unaudited Pro Forma Information (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-3-acquisitions-unaudited-pro-forma-information-details </Role> |
| | | <ShortName> Note 3 - Acquisitions - Unaudited Pro Forma Information (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 51 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R52.htm </HtmlFileName> |
| | | <LongName> 051 - Disclosure - Note 4 - Redeemable Noncontrolling Interest (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-4-redeemable-noncontrolling-interest-details-textual </Role> |
| | | <ShortName> Note 4 - Redeemable Noncontrolling Interest (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-4-redeemable-noncontrolling-interest-tables </ParentRole> |
| | | <Position> 52 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R53.htm </HtmlFileName> |
| | | <LongName> 052 - Disclosure - Note 4 - Redeemable Noncontrolling Interest - Redeemable Noncontrolling Interest (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-4-redeemable-noncontrolling-interest-redeemable-noncontrolling-interest-details </Role> |
| | | <ShortName> Note 4 - Redeemable Noncontrolling Interest - Redeemable Noncontrolling Interest (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 53 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R54.htm </HtmlFileName> |
| | | <LongName> 053 - Disclosure - Note 5 - Derivative Instruments and Hedging Activities (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-5-derivative-instruments-and-hedging-activities-details-textual </Role> |
| | | <ShortName> Note 5 - Derivative Instruments and Hedging Activities (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-5-derivative-instruments-and-hedging-activities-tables </ParentRole> |
| | | <Position> 54 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R55.htm </HtmlFileName> |
| | | <LongName> 054 - Disclosure - Note 5 - Derivative Instruments and Hedging Activities - Fair Value of Derivatives (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-5-derivative-instruments-and-hedging-activities-fair-value-of-derivatives-details </Role> |
| | | <ShortName> Note 5 - Derivative Instruments and Hedging Activities - Fair Value of Derivatives (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 55 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R56.htm </HtmlFileName> |
| | | <LongName> 055 - Disclosure - Note 6 - Accumulated Other Comprehensive Loss (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss-details-textual </Role> |
| | | <ShortName> Note 6 - Accumulated Other Comprehensive Loss (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss-tables </ParentRole> |
| | | <Position> 56 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R57.htm </HtmlFileName> |
| | | <LongName> 056 - Disclosure - Note 6 - Accumulated Other Comprehensive Loss - Disclosure of Changes in Accumulated Other Comprehensive Loss (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss-disclosure-of-changes-in-accumulated-other-comprehensive-loss-details </Role> |
| | | <ShortName> Note 6 - Accumulated Other Comprehensive Loss - Disclosure of Changes in Accumulated Other Comprehensive Loss (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 57 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R58.htm </HtmlFileName> |
| | | <LongName> 057 - Disclosure - Note 6 - Accumulated Other Comprehensive Loss - Reclassifications from AOCL (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-6-accumulated-other-comprehensive-loss-reclassifications-from-aocl-details </Role> |
| | | <ShortName> Note 6 - Accumulated Other Comprehensive Loss - Reclassifications from AOCL (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 58 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R59.htm </HtmlFileName> |
| | | <LongName> 058 - Disclosure - Note 7 - Segment Reporting (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-7-segment-reporting-details-textual </Role> |
| | | <ShortName> Note 7 - Segment Reporting (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-7-segment-reporting-tables </ParentRole> |
| | | <Position> 59 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R60.htm </HtmlFileName> |
| | | <LongName> 059 - Disclosure - Note 7 - Segment Reporting - Net Sales by Products and Services (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-7-segment-reporting-net-sales-by-products-and-services-details </Role> |
| | | <ShortName> Note 7 - Segment Reporting - Net Sales by Products and Services (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 60 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R61.htm </HtmlFileName> |
| | | <LongName> 060 - Disclosure - Note 7 - Segment Reporting - Segment Information (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-7-segment-reporting-segment-information-details </Role> |
| | | <ShortName> Note 7 - Segment Reporting - Segment Information (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 61 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R62.htm </HtmlFileName> |
| | | <LongName> 061 - Disclosure - Note 8 - Balance Sheet Details (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details-details-textual </Role> |
| | | <ShortName> Note 8 - Balance Sheet Details (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details-tables </ParentRole> |
| | | <Position> 62 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R63.htm </HtmlFileName> |
| | | <LongName> 062 - Disclosure - Note 8 - Balance Sheet Details - Inventories (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details-inventories-details </Role> |
| | | <ShortName> Note 8 - Balance Sheet Details - Inventories (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 63 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R64.htm </HtmlFileName> |
| | | <LongName> 063 - Disclosure - Note 8 - Balance Sheet Details - Property and Equipment (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-8-balance-sheet-details-property-and-equipment-details </Role> |
| | | <ShortName> Note 8 - Balance Sheet Details - Property and Equipment (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 64 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R65.htm </HtmlFileName> |
| | | <LongName> 064 - Disclosure - Note 9 - Goodwill and Intangible Assets (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets-details-textual </Role> |
| | | <ShortName> Note 9 - Goodwill and Intangible Assets (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets-tables </ParentRole> |
| | | <Position> 65 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R66.htm </HtmlFileName> |
| | | <LongName> 065 - Disclosure - Note 9 - Goodwill and Intangible Assets - Carrying Amount of Goodwill (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets-carrying-amount-of-goodwill-details </Role> |
| | | <ShortName> Note 9 - Goodwill and Intangible Assets - Carrying Amount of Goodwill (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 66 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R67.htm </HtmlFileName> |
| | | <LongName> 066 - Disclosure - Note 9 - Goodwill and Intangible Assets - Summary of Intangible Assets (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-9-goodwill-and-intangible-assets-summary-of-intangible-assets-details </Role> |
| | | <ShortName> Note 9 - Goodwill and Intangible Assets - Summary of Intangible Assets (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 67 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R68.htm </HtmlFileName> |
| | | <LongName> 067 - Disclosure - Note 10 - Leases (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-details-textual </Role> |
| | | <ShortName> Note 10 - Leases (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-10-leases-tables </ParentRole> |
| | | <Position> 68 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R69.htm </HtmlFileName> |
| | | <LongName> 068 - Disclosure - Note 10 - Leases - Leases Cost (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-leases-cost-details </Role> |
| | | <ShortName> Note 10 - Leases - Leases Cost (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 69 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R70.htm </HtmlFileName> |
| | | <LongName> 069 - Disclosure - Note 10 - Leases - Supplement Balance Sheet Information Related to Leases (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-supplement-balance-sheet-information-related-to-leases-details </Role> |
| | | <ShortName> Note 10 - Leases - Supplement Balance Sheet Information Related to Leases (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 70 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R71.htm </HtmlFileName> |
| | | <LongName> 070 - Disclosure - Note 10 - Leases - Supplement Cash Flow Information Related to Leases (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-supplement-cash-flow-information-related-to-leases-details </Role> |
| | | <ShortName> Note 10 - Leases - Supplement Cash Flow Information Related to Leases (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 71 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R72.htm </HtmlFileName> |
| | | <LongName> 071 - Disclosure - Note 10 - Leases - Weighted Average Remaining Lease Term and Discount Rate Information (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-weighted-average-remaining-lease-term-and-discount-rate-information-details </Role> |
| | | <ShortName> Note 10 - Leases - Weighted Average Remaining Lease Term and Discount Rate Information (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 72 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R73.htm </HtmlFileName> |
| | | <LongName> 072 - Disclosure - Note 10 - Leases - Maturities of Lease liabilities (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-10-leases-maturities-of-lease-liabilities-details </Role> |
| | | <ShortName> Note 10 - Leases - Maturities of Lease liabilities (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 73 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R74.htm </HtmlFileName> |
| | | <LongName> 073 - Disclosure - Note 11 - Product Warranty Obligations 1 (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-1-details-textual </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations 1 (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-tables </ParentRole> |
| | | <Position> 74 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R75.htm </HtmlFileName> |
| | | <LongName> 074 - Disclosure - Note 11 - Product Warranty Obligations 2 (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-2-details-textual </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations 2 (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-tables </ParentRole> |
| | | <Position> 75 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R76.htm </HtmlFileName> |
| | | <LongName> 075 - Disclosure - Note 11 - Product Warranty Obligations - Reconciliation of Product Warranty Liability (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-reconciliation-of-product-warranty-liability-details </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations - Reconciliation of Product Warranty Liability (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 76 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R77.htm </HtmlFileName> |
| | | <LongName> 076 - Disclosure - Note 11 - Product Warranty Obligations - Recognition of Deferred Revenue Related to Extended Warranties (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-recognition-of-deferred-revenue-related-to-extended-warranties-details </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations - Recognition of Deferred Revenue Related to Extended Warranties (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 77 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R78.htm </HtmlFileName> |
| | | <LongName> 077 - Disclosure - Note 11 - Product Warranty Obligations - Recognition of Deferred Revenue Related to Extended Warranties 2 (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-recognition-of-deferred-revenue-related-to-extended-warranties-2-details </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations - Recognition of Deferred Revenue Related to Extended Warranties 2 (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 78 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R79.htm </HtmlFileName> |
| | | <LongName> 078 - Disclosure - Note 11 - Product Warranty Obligations - Deferred Product Obligations (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-11-product-warranty-obligations-deferred-product-obligations-details </Role> |
| | | <ShortName> Note 11 - Product Warranty Obligations - Deferred Product Obligations (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 79 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R80.htm </HtmlFileName> |
| | | <LongName> 079 - Disclosure - Note 12 - Credit Agreements (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-12-credit-agreements-details-textual </Role> |
| | | <ShortName> Note 12 - Credit Agreements (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-12-credit-agreements-tables </ParentRole> |
| | | <Position> 80 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R81.htm </HtmlFileName> |
| | | <LongName> 080 - Disclosure - Note 12 - Credit Agreements - Short-term Borrowings (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-12-credit-agreements-shortterm-borrowings-details </Role> |
| | | <ShortName> Note 12 - Credit Agreements - Short-term Borrowings (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 81 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R82.htm </HtmlFileName> |
| | | <LongName> 081 - Disclosure - Note 12 - Credit Agreements - Long-term Borrowings (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-12-credit-agreements-longterm-borrowings-details </Role> |
| | | <ShortName> Note 12 - Credit Agreements - Long-term Borrowings (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 82 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R83.htm </HtmlFileName> |
| | | <LongName> 082 - Disclosure - Note 12 - Credit Agreements - Maturities of Long-term Borrowings Outstanding (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-12-credit-agreements-maturities-of-longterm-borrowings-outstanding-details </Role> |
| | | <ShortName> Note 12 - Credit Agreements - Maturities of Long-term Borrowings Outstanding (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 83 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R84.htm </HtmlFileName> |
| | | <LongName> 083 - Disclosure - Note 13 - Stock Repurchase Programs (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-13-stock-repurchase-programs-details-textual </Role> |
| | | <ShortName> Note 13 - Stock Repurchase Programs (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-13-stock-repurchase-programs </ParentRole> |
| | | <Position> 84 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R85.htm </HtmlFileName> |
| | | <LongName> 084 - Disclosure - Note 14 - Earnings Per Share (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-14-earnings-per-share-details-textual </Role> |
| | | <ShortName> Note 14 - Earnings Per Share (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-14-earnings-per-share-tables </ParentRole> |
| | | <Position> 85 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R86.htm </HtmlFileName> |
| | | <LongName> 085 - Disclosure - Note 14 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-14-earnings-per-share-reconciliation-of-basic-and-diluted-earnings-per-share-details </Role> |
| | | <ShortName> Note 14 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 86 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R87.htm </HtmlFileName> |
| | | <LongName> 086 - Disclosure - Note 15 - Income Taxes (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes-details-textual </Role> |
| | | <ShortName> Note 15 - Income Taxes (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-15-income-taxes-tables </ParentRole> |
| | | <Position> 87 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R88.htm </HtmlFileName> |
| | | <LongName> 087 - Disclosure - Note 15 - Income Taxes - Provision for Income Taxes (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes-provision-for-income-taxes-details </Role> |
| | | <ShortName> Note 15 - Income Taxes - Provision for Income Taxes (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 88 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R89.htm </HtmlFileName> |
| | | <LongName> 088 - Disclosure - Note 15 - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes-components-of-deferred-tax-assets-and-liabilities-details </Role> |
| | | <ShortName> Note 15 - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 89 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R90.htm </HtmlFileName> |
| | | <LongName> 089 - Disclosure - Note 15 - Income Taxes - Unrecognized Tax Benefits (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes-unrecognized-tax-benefits-details </Role> |
| | | <ShortName> Note 15 - Income Taxes - Unrecognized Tax Benefits (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 90 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R91.htm </HtmlFileName> |
| | | <LongName> 090 - Disclosure - Note 15 - Income Taxes - Reconciliation of Statutory and Effective Tax Rates (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-15-income-taxes-reconciliation-of-statutory-and-effective-tax-rates-details </Role> |
| | | <ShortName> Note 15 - Income Taxes - Reconciliation of Statutory and Effective Tax Rates (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 91 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R92.htm </HtmlFileName> |
| | | <LongName> 091 - Disclosure - Note 16 - Benefit Plans (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-16-benefit-plans-details-textual </Role> |
| | | <ShortName> Note 16 - Benefit Plans (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-16-benefit-plans </ParentRole> |
| | | <Position> 92 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R93.htm </HtmlFileName> |
| | | <LongName> 092 - Disclosure - Note 17 - Share Plans (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-17-share-plans-details-textual </Role> |
| | | <ShortName> Note 17 - Share Plans (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-17-share-plans-tables </ParentRole> |
| | | <Position> 93 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R94.htm </HtmlFileName> |
| | | <LongName> 093 - Disclosure - Note 17 - Share Plans - Weighted-average Assumptions used in the Black-Scholes-Merton Option Pricing Model (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-17-share-plans-weightedaverage-assumptions-used-in-the-blackscholesmerton-option-pricing-model-details </Role> |
| | | <ShortName> Note 17 - Share Plans - Weighted-average Assumptions used in the Black-Scholes-Merton Option Pricing Model (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 94 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R95.htm </HtmlFileName> |
| | | <LongName> 094 - Disclosure - Note 17 - Share Plans - Summary of Stock Option Activity (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-17-share-plans-summary-of-stock-option-activity-details </Role> |
| | | <ShortName> Note 17 - Share Plans - Summary of Stock Option Activity (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 95 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R96.htm </HtmlFileName> |
| | | <LongName> 095 - Disclosure - Note 17 - Share Plans - Summary of Restricted Share Awards Activity (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-17-share-plans-summary-of-restricted-share-awards-activity-details </Role> |
| | | <ShortName> Note 17 - Share Plans - Summary of Restricted Share Awards Activity (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 96 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R97.htm </HtmlFileName> |
| | | <LongName> 096 - Disclosure - Note 18 - Commitments and Contingencies (Details Textual) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-18-commitments-and-contingencies-details-textual </Role> |
| | | <ShortName> Note 18 - Commitments and Contingencies (Details Textual) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-18-commitments-and-contingencies </ParentRole> |
| | | <Position> 97 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R98.htm </HtmlFileName> |
| | | <LongName> 097 - Disclosure - Note 19 - Quarterly Financial Information (Unaudited) - Unaudited Quarterly Financial Information (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-19-quarterly-financial-information-unaudited-unaudited-quarterly-financial-information-details </Role> |
| | | <ShortName> Note 19 - Quarterly Financial Information (Unaudited) - Unaudited Quarterly Financial Information (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <ParentRole> http://www.generac.com/20201231/role/statement-note-19-quarterly-financial-information-unaudited-tables </ParentRole> |
| | | <Position> 98 </Position> |
| | | </Report> |
| | <Report instance="gnrc20201231_10k.htm"> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <HtmlFileName> R99.htm </HtmlFileName> |
| | | <LongName> 098 - Disclosure - Note 20 - Valuation and Qualifying Accounts - Schedule of Valuation and Qualifying Accounts (Details) </LongName> |
| | | <ReportType> Sheet </ReportType> |
| | | <Role> http://www.generac.com/20201231/role/statement-note-20-valuation-and-qualifying-accounts-schedule-of-valuation-and-qualifying-accounts-details </Role> |
| | | <ShortName> Note 20 - Valuation and Qualifying Accounts - Schedule of Valuation and Qualifying Accounts (Details) </ShortName> |
| | | <MenuCategory> Details </MenuCategory> |
| | | <Position> 99 </Position> |
| | | </Report> |
| | <Report> |
| | | <IsDefault> false </IsDefault> |
| | | <HasEmbeddedReports> false </HasEmbeddedReports> |
| | | <LongName> All Reports </LongName> |
| | | <ReportType> Book </ReportType> |
| | | <ShortName> All Reports </ShortName> |
| | | </Report> |
| | </MyReports> |
| <InputFiles> |
| | <File doctype="10-K" original="gnrc20201231_10k.htm"> gnrc20201231_10k.htm </File> |
| | <File> ex_215590.htm </File> |
| | <File> ex_215591.htm </File> |
| | <File> ex_215592.htm </File> |
| | <File> ex_215593.htm </File> |
| | <File> ex_215594.htm </File> |
| | <File> ex_215595.htm </File> |
| | <File> gnrc-20201231.xsd </File> |
| | <File> gnrc-20201231_cal.xml </File> |
| | <File> gnrc-20201231_def.xml </File> |
| | <File> gnrc-20201231_lab.xml </File> |
| | <File> gnrc-20201231_pre.xml </File> |
| | </InputFiles> |
| <SupplementalFiles> |
| | <File> totalreturngraph.jpg </File> |
| | </SupplementalFiles> |
| <BaseTaxonomies> |
| | <BaseTaxonomy> http://fasb.org/us-gaap/2020-01-31 </BaseTaxonomy> |
| | <BaseTaxonomy> http://xbrl.sec.gov/dei/2019-01-31 </BaseTaxonomy> |
| | <BaseTaxonomy> http://fasb.org/srt/2020-01-31 </BaseTaxonomy> |
| | <BaseTaxonomy> http://xbrl.sec.gov/country/2020-01-31 </BaseTaxonomy> |
| | </BaseTaxonomies> |
| <HasPresentationLinkbase> true </HasPresentationLinkbase> |
| <HasCalculationLinkbase> true </HasCalculationLinkbase> |
| </FilingSummary> |