Income Tax Disclosure [Abstract] Income before taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income taxes at U.S. federal statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Tax on income not subject to entity level federal income tax Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Meals & Entertainment Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment, Amount Non-deductible stock compensation costs Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount State income tax, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Other Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Income Tax Expense Income Tax Expense (Benefit) Less: income prior to the Reorganization Transactions Income (Loss), Before Reorganization Transactions, Before Income Taxes Income (Loss), Before Reorganization Transactions, Before Income Taxes Less: income attributable to non-controlling interests Income (Loss) Attributable to Noncontrolling Interest, before Tax (Loss) Income attributable to Goosehead Insurance, Inc. before taxes Income (Loss) Attributable to Parent, before Tax State and local income taxes, net of federal benefit Current Federal, State and Local, Tax Expense (Benefit) Permanent differences Income Tax Reconciliation, Permanent Differences, Amount Income Tax Reconciliation, Permanent Differences, Amount Income tax expense Income Tax Expense (Benefit), Portion Attributable To Parent Income Tax Expense (Benefit), Portion Attributable To Parent Effective Income Tax Rate Reconciliation, Nondeductible Expense, Excess Compensation, Amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Excess Compensation, Amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Excess Compensation, Amount Receivables [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Agency Fees Agency Fees Receivables [Member] Agency Fees Receivables Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Beginning balance Accounts Receivable, Allowance for Credit Loss Bad debt expense Accounts Receivable, Credit Loss Expense (Reversal) Write offs Accounts Receivable, Allowance for Credit Loss, Writeoff Ending balance Financing Receivable, Allowance for Credit Loss [Table] Financing Receivable, Allowance for Credit Loss [Table] Franchise Fees Receivable Franchise Fees Receivable [Member] Franchise Fees Receivable [Member] Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable, Allowance for Credit Loss [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] Beginning balance Financing Receivable, Allowance for Credit Loss Charges to bad debts Provision for Loan, Lease, and Other Losses Write offs Financing Receivable, Allowance for Credit Loss, Writeoff Ending balance Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Line of Credit Line of Credit [Member] Secured Debt Secured Debt [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maximum borrowing availability Line of Credit Facility, Maximum Borrowing Capacity Principal amount of debt Debt Instrument, Face Amount Additional commitments Line Of Credit Facility, Maximum Borrowing Capacity, Additional Commitments Line Of Credit Facility, Maximum Borrowing Capacity, Additional Commitments Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Leverage ratio Leverage Ratio Leverage Ratio Revolver balance Long-term Line of Credit Remaining borrowing availability Line of Credit Facility, Remaining Borrowing Capacity Letter of credit Letters of Credit Outstanding, Amount Interest expense Interest Expense, Debt Aggregate principal amount Long-term Debt, Gross Quarterly payments, next twelve months Debt Instrument, Periodic Payment, Principal, Year Two Debt Instrument, Periodic Payment, Principal, Year Two Quarterly payments, last twelve months Debt Instrument, Periodic Payment, Principal, Year Three Debt Instrument, Periodic Payment, Principal, Year Three Debt issuance costs Debt Issuance Costs, Net Amortization period Debt Issuance Costs, Amortization Period Debt Issuance Costs, Amortization Period Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Misclassification of distributions to non-controlling interest [Member] Misclassification of distributions to non-controlling interest [Member] Misclassification of distributions to non-controlling interest Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Members' deficit Member Units [Member] Common stock Common Stock [Member] Additional paid in capital Additional Paid-in Capital [Member] Accumulated deficit Retained Earnings [Member] Total stockholders' equity Parent [Member] Non-controlling interest Noncontrolling Interest [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock Class of Stock [Domain] Class A Common Stock Common Class A [Member] Class B Common Stock Common Class B [Member] Statement [Line Items] Statement [Line Items] Stock Issued During Period, Value, Effects Of The Reorganization Transaction Stock Issued During Period, Value, Effects Of The Reorganization Transaction Stock Issued During Period, Value, Effects Of The Reorganization Transaction Noncontrolling Interest, Increase from Subsidiary Equity Issuance Noncontrolling Interest, Increase from Subsidiary Equity Issuance Stock Issued During Period, Shares, New Issues Stock Issued During Period, Shares, New Issues Stock Issued During Period, Value, New Issues Stock Issued During Period, Value, New Issues Stock Issued During Period, Shares, Effects Of The Reorganization Transaction Stock Issued During Period, Shares, Effects Of The Reorganization Transaction Stock Issued During Period, Shares, Effects Of The Reorganization Transaction Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Beginning balance (in shares) Shares, Outstanding Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Distributions Dividends Dividends declared Dividends, Common Stock, Cash Equity-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Activity under employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Stock Issued During Period, Value, Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Redemption of LLC Units (in shares) Stock Redeemed or Called During Period, Shares Redemption of LLC Units Stock Redeemed or Called During Period, Value Deferred tax adjustments related to Tax Receivable Agreement Adjustments To Additional Paid In Capital, Tax Receivable Agreement Adjustments To Additional Paid In Capital, Tax Receivable Agreement Ending balance Ending balance (in shares) Equity [Abstract] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Earnings Per Share [Abstract] Summary of total estimated dividends to be paid Dividends Declared [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Goosehead Insurance, Inc. Goosehead Insurance, Inc. [Member] Goosehead Insurance, Inc. [Member] Pre-IPO LLC Members Pre-IPO LLC Members [Member] Pre-IPO LLC Members [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Goosehead Financial, LLC Goosehead Financial, LLC [Member] Goosehead Financial, LLC [Member] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Initial Public Offering IPO [Member] Over-Allotment Option Over-Allotment Option [Member] Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Shares issued (in shares) Sale of Stock, Number of Shares Issued in Transaction Share price (in dollars per share) Sale of Stock, Price Per Share Ownership interest Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Corporate-owned locations Number Of Corporate-Owned Locations Number Of Corporate-Owned Locations Franchise locations sold Significant Changes, Franchises Sold Operating franchise locations Significant Changes, Franchised Outlets in Operation Franchises purchased Significant Changes, Franchises Purchased During Period Accounting Policies [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Cash Equivalents, Current Cash and cash equivalents, and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Future minimum operating lease commitments Operating Leases, Future Minimum Payments Due Basis of Combination Consolidation, Policy [Policy Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Recently Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Framework for Measuring Fair Value Fair Value Measurement, Policy [Policy Text Block] Segment Reporting [Abstract] Number of reportable segments Number of Reportable Segments Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Commissions and agency fees Commissions And Agency Fees [Member] Commissions And Agency Fees [Member] Franchise revenues Franchise [Member] Interest income Interest Income1 [Member] Interest Income1 Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Other Corporate And Reconciling Items [Member] Corporate And Reconciling Items [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Corporate Channel Corporate Channel [Member] Corporate Channel [Member] Franchise Channel Franchise Channel [Member] Franchise Channel [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Revenues: Revenues [Abstract] Revenues Revenues Operating Expenses: Operating Expenses [Abstract] Employee compensation and benefits, excluding equity-based compensation Employee Compensation And Benefits, Excluding Share-based Compensation Employee Compensation And Benefits, Excluding Share-based Compensation General and administrative expenses General and Administrative Expense Bad debts Total operating expenses Operating Expenses, Excluding Depreciation, Depletion, And Amortization Operating Expenses, Excluding Depreciation, Depletion, And Amortization Adjusted EBITDA Earnings Before Interest, Taxes, Depreciation, And Amortization Earnings Before Interest, Taxes, Depreciation, And Amortization Equity-based compensation Share-based Payment Arrangement, Expense Interest expense Interest Expense Depreciation and amortization Depreciation, Depletion And Amortization, Excluding Debt Issuance Cost Amortization Depreciation, Depletion And Amortization, Excluding Debt Issuance Cost Amortization Taxes Net income (loss) Total Assets Assets Summary of Pro Forma Ownership Interest Schedule of Weighted Average Number of Shares [Table Text Block] Schedule of Calculation of EPS and Pro Forma EPS Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table Text Block] Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Furniture & fixtures Furniture and Fixtures [Member] Computer equipment Computer Equipment [Member] Network equipment Network Equipment [Member] Network Equipment [Member] Phone system Phone System [Member] Phone System [Member] Leasehold improvements Leasehold Improvements [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property and equipment, gross Property, Plant and Equipment, Gross Less accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, net Property, Plant and Equipment, Net Cover page. Entities [Table] Entities [Table] Entity Information [Line Items] Entity Information [Line Items] Document Type Document Type Document Quarterly Report Document Quarterly Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Address Line One Entity Address, Address Line One Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Ex Transition Period Entity Ex Transition Period Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Segment Information Segment Reporting Disclosure [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Franchise Fees Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Parent Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Pro forma number of LLC Units outstanding (in shares) Weighted Average General Partnership Units Outstanding Ownership interest held by Goosehead Insurance, Inc. Noncontrolling Interest, Ownership Percentage by Parent Ownership interest held by non-controlling interest holders Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Ownership interest Noncontrolling Interest, Ownership Percentage Noncontrolling Interest, Ownership Percentage Income Tax Contingency [Table] Income Tax Contingency [Table] LLC Units LLC Units [Member] LLC Units [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Tax Receivable Agreement Tax Receivable Agreement [Member] Tax Receivable Agreement [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Uncertain tax positions Unrecognized Tax Benefits Percentage due to related parties Related Party Transaction, Percentage Due To Related Parties Related Party Transaction, Percentage Due To Related Parties Due to related parties Due to Related Parties Due to related parties, current Due to Related Parties, Current Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Statement of Financial Position [Abstract] Common stock par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock shares authorized (in shares) Common Stock, Shares Authorized Common stock shares issued (in shares) Common Stock, Shares, Issued Common stock shares outstanding (in shares) Common Stock, Shares, Outstanding Assets Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and cash equivalents Restricted cash Restricted Cash, Current Commissions and agency fees receivable, net Accounts Receivable, Net, Current - Commissions And Agency Fees Receivable Accounts Receivable, Net, Current - Commissions And Agency Fees Receivable Receivable from franchisees, net Accounts Receivable, Net, Current - Franchise Receivable Accounts Receivable, Net, Current - Franchise Receivable Prepaid expenses Prepaid Expense, Current Total current assets Assets, Current Receivable from franchisees, net of current portion Accounts Receivable, Net, Noncurrent - Franchise Receivable Accounts Receivable, Net, Noncurrent - Franchise Receivable Property and equipment, net of accumulated depreciation Intangible assets, net of accumulated amortization Intangible Assets, Net (Excluding Goodwill) Deferred income taxes, net Deferred Income Tax Assets, Net Other assets Other Assets, Noncurrent Total assets Liabilities and Stockholders’ Equity Liabilities and Equity [Abstract] Current Liabilities: Liabilities, Current [Abstract] Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities, Current Premiums payable Premiums Payable, Current Premiums Payable, Current Unearned revenue Contract with Customer, Liability, Current Deferred rent Deferred Rent Credit, Current Note payable Long-term Debt, Current Maturities Total current liabilities Liabilities, Current Deferred rent, net of current portion Deferred Rent Credit, Noncurrent Note payable, net of current portion Long-term Debt, Excluding Current Maturities Liabilities under tax receivable agreement, net of current portion Due to Related Parties, Noncurrent Total liabilities Liabilities Commitments and contingencies (see note 7) Commitments and Contingencies Common stock Common Stock, Value, Issued Additional paid in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Total stockholders' equity Stockholders' Equity Attributable to Parent Non-controlling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Total liabilities and stockholders' equity Liabilities and Equity Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Consolidation, Eliminations Consolidation, Eliminations [Member] Misclassification of distributions to non-controlling interest Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Weighted Average Weighted Average [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Weighted Average General Partnership Units Outstanding Vote per share Common Stock, Vote Per Share Common Stock, Vote Per Share Distributions Payments of Distributions to Affiliates Conversion ratio Sale Of Stock, Conversion Of Existing Interests, Conversion Ratio Sale Of Stock, Conversion Of Existing Interests, Conversion Ratio Redemption of LLC Units (in shares) Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income (loss) Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Equity-based compensation Share-based Payment Arrangement, Noncash Expense Adjustments to tax receivable agreement liability Increase (Decrease) in Due to Related Parties Deferred income taxes Deferred Income Tax Expense (Benefit) Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Commissions and agency fees receivable Increase (Decrease) In Accounts Receivable - Commissions And Agency Fees Receivable Increase (Decrease) In Accounts Receivable - Commissions And Agency Fees Receivable Receivable from franchisees Increase (Decrease) In Accounts Receivable - Franchise Receivable Increase (Decrease) In Accounts Receivable - Franchise Receivable Prepaid expenses Increase (Decrease) in Prepaid Expense Other assets Increase (Decrease) in Other Operating Assets Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Deferred rent Increase (Decrease) In Deferred Rent Credit Increase (Decrease) In Deferred Rent Credit Premiums payable Increase (Decrease) In Premiums Payable Increase (Decrease) In Premiums Payable Unearned revenue Increase (Decrease) in Contract with Customer, Liability Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from notes receivable Proceeds from Sale and Collection of Notes Receivable Purchase of software Payments for Software Purchase of property and equipment Payments to Acquire Property, Plant, and Equipment Net cash used for investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Loan origination fees Amortization of Debt Issuance Costs Repayment of note payable Repayments of Secured Debt Proceeds from the issuance of Class A common stock Proceeds from Issuance Initial Public Offering Member distributions and dividends Payments of Dividends Net cash provided by (used for) financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents, and restricted cash, beginning of period Cash and cash equivalents, and restricted cash, end of period Supplemental disclosures of cash flow data: Supplemental Cash Flow Information [Abstract] Cash paid during the year for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Cash paid for income taxes Income Taxes Paid Management fee note repayment through issuance of Class A common stock Stock Issued Income Statement [Abstract] Employee compensation and benefits (including Class B unit compensation of $0 for the three and six months ended June 30, 2019 and $26,134 for the three and six months ended June 30, 2018) Labor and Related Expense Depreciation and amortization Total operating expenses Operating Expenses Income (loss) from operations Operating Income (Loss) Other Income (Expense): Other Nonoperating Income (Expense) [Abstract] Income (loss) before taxes Tax expense Less: net income (loss) attributable to non-controlling interests Net Income (Loss) Attributable to Noncontrolling Interest Net income (loss) attributable to Goosehead Insurance, Inc. Net Income (Loss) Attributable to Parent Earnings (loss) per share: Earnings Per Share, Basic and Diluted [Abstract] Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Weighted average shares of Class A common stock outstanding Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Dividends declared per share (in dollars per share) Common Stock, Dividends, Per Share, Declared 2019 Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 2020 Long-term Debt, Maturities, Repayments of Principal in Year Two 2021 Long-term Debt, Maturities, Repayments of Principal in Year Three Total Share-based Payment Arrangement [Abstract] Equity-Based Compensation Share-based Payment Arrangement [Text Block] Income Taxes Income Tax Disclosure [Text Block] Schedule of Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Future Minimum Lease Payments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Note Payable Debt Disclosure [Text Block] Franchise fees receivable Financing Receivable, before Allowance for Credit Loss Less: Unamortized discount Receivable with Imputed Interest, Discount Less: Allowance for uncollectible franchise fees Total franchise fees receivable Financing Receivable, after Allowance for Credit Loss Schedule of Allowance for Uncollectible Agency Fees Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Common Class B Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Employee Stock Option Share-based Payment Arrangement, Option [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Equity-based compensation expense Litigation Legal Matters and Contingencies [Text Block] Schedule of Franchise Fees Receivable Schedule of Allowance For Uncollectible Franchise Fees Financing Receivable, Allowance for Credit Loss [Table Text Block] Pro forma earnings per share: Earnings Per Share, Pro Forma [Abstract] Income (Loss) Before Income Taxes, Attributable To Noncontrolling Interest Income (Loss) Before Income Taxes, Attributable To Noncontrolling Interest Income (Loss) Before Income Taxes, Attributable To Noncontrolling Interest Net Income (Loss) Before Income Taxes, Attributable To Parent Net Income (Loss) Before Income Taxes, Attributable To Parent Net Income (Loss) Before Income Taxes, Attributable To Parent Less: income tax expense attributable to GSHD Net income (loss) attributable to Goosehead Insurance, Inc. Net Income (Loss) Available to Common Stockholders, Basic Weighted average shares of Class A common stock outstanding - basic (in shares) Effect of dilutive securities (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average shares of Class A common stock outstanding - diluted (in shares) Earnings per share of Class A common stock - basic (in dollars per share) Earnings per share of Class A common stock - diluted (in dollars per share) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Leverage Ratio Threshold [Axis] Leverage Ratio Threshold [Axis] Leverage Ratio Threshold [Axis] Leverage Ratio Threshold [Domain] Leverage Ratio Threshold [Domain] [Domain] for Leverage Ratio Threshold [Axis] Less than 1.50 Threshold One [Member] Threshold One [Member] Greater than 1.50 Threshold Two [Member] Threshold Two [Member] Greater than 2.50 Threshold Three [Member] Threshold Three [Member] Greater than 3.50 Threshold Four [Member] Threshold Four [Member] Schedule of Property and Equipment Property, Plant and Equipment [Table Text Block] Schedule of Interest Rate Dependent of Leverage Ratio Schedule Of Interest Rate Dependent Of Leverage Ratio [Table Text Block] Schedule Of Interest Rate Dependent Of Leverage Ratio [Table Text Block] Schedule of Maturities of Note Payable Schedule of Maturities of Long-term Debt [Table Text Block] Rent expense Operating Leases, Rent Expense Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2019 Operating Leases, Future Minimum Payments, Remainder of Fiscal Year 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years 2024-2029 Operating Leases Future Minimum Payments Due In Six To Twelve Years Operating Leases Future Minimum Payments Due In Six To Twelve Years Total Allowance for Uncollectible Agency Fees Summary of Equity-Based Compensation Expense Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Investment in flow-through entity Deferred Tax Assets, Investment in Subsidiaries Net deferred tax asset (liability) Deferred Tax Assets, Net Schedule of Reconciliation of Income Tax Expense Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Income before Income Taxes Schedule Of Income Before Income Taxes [Table Text Block] Schedule Of Income Before Income Taxes [Table Text Block] Schedule of Components of Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Restrictions on Cash and Cash Equivalents Restrictions on Cash and Cash Equivalents [Table Text Block] Schedule of Reconciliation of Cash and Restricted Cash Schedule of Cash and Cash Equivalents [Table Text Block] Property and equipment Property, Plant and Equipment Disclosure [Text Block] Dividends Payable [Table] Dividends Payable [Table] Dividends Payable [Line Items] Dividends Payable [Line Items] Dividends Dividends, Cash LLC Units held (in shares) Dividends Dividends [Text Block] Dividends [Text Block]