Term Loan, Maturing December 2024 Term Loan Maturing December2024 [Member] Represents information pertaining to a Term Loan maturing December 2024. Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Work in progress Inventory, Work in Process, Gross Earnings per Share Earnings Per Share, Policy [Policy Text Block] Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Leasehold improvements Leasehold Improvements [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Net income attributable to Karat Packaging Inc. Net income attributable to Karat Packaging Inc. Net Income (Loss) Attributable to Parent Consolidated Entities [Axis] Consolidated Entities [Axis] Entity Emerging Growth Company Entity Emerging Growth Company Distribution centers operated by entity Number Of Other Distribution Centers Operated By Entity Represents the number of other distribution centers operated by entity. Income Statement Location [Axis] Income Statement Location [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Entity Address, Address Line One Entity Address, Address Line One Marketing and Advertising Expense [Abstract] Marketing and Advertising Expense [Abstract] Schedule of future maturities Schedule of Maturities of Long-term Debt [Table Text Block] Reporting Segment Segment Reporting, Policy [Policy Text Block] Cash dividends Dividends, Common Stock, Cash Proceeds on disposal of property and equipment Proceeds from Sale of Property, Plant, and Equipment Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Entity Filer Category Entity Filer Category Earnings Per Share Reconciliation [Abstract] Earnings Per Share Reconciliation [Abstract] Canceled/forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Foreign Currency Foreign Currency Transactions and Translations Policy [Policy Text Block] Treasury stock, par value (in dollars per share) Treasury Stock, Par or Stated Value Per Share Face amount or stated value per share of treasury stock. Credit cards payable Credit Cards Payable, Current Amount of credit cards payable due within one year or the normal operating cycle, if longer. Other assets (including $0.0 million and $0.1 million associated with variable interest entity at September 30, 2021 and December 31, 2020) Other assets Other Assets, Noncurrent Obligations under Capital Leases Capital Lease Obligations Disclosure [Text Block] The entire disclosure for capital lease obligations. Investment, Name [Axis] Investment, Name [Axis] Minimum exercise price to fair market value of common stock at the date of grant Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercise Price, Percentage of Fair Market Value, Minimum, Grant Date Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercise Price, Percentage of Fair Market Value, Minimum, Grant Date Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Derivative Instruments Derivatives, Policy [Policy Text Block] Property held under capital leases Property Held Under Capital Leases [Member] Represent information pertaining to property held under capital leases. Net increase in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect 2023 Long-Term Debt, Maturity, Year Two Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition National National Distribution [Member] Represents information pertaining to National Distribution. Income taxes payable Increase (Decrease) in Income Taxes Payable Gain on sales of asset Gain (Loss) on Disposition of Assets 2021 (remainder) Long-Term Debt, Maturity, Remainder of Fiscal Year Document Fiscal Year Focus Document Fiscal Year Focus Subsequent Event Type [Domain] Subsequent Event Type [Domain] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Future maturities: Maturities of Long-term Debt [Abstract] Customer relationships Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Potentially dilutive shares excluded from diluted earnings per share calculation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of inventories Schedule of Inventory, Current [Table Text Block] Money market deposits, exceeding federally insured limits Deposits, Money Market Deposits, Above US Insurance Limits Deposits, Money Market Deposits, Above US Insurance Limits Subsequent Events [Abstract] Subsequent Events [Abstract] Building Building [Member] Variable interest entity, number of entities Variable Interest Entity, Number Of Entities Variable Interest Entity, Number Of Entities Effective income tax rate, reduction Effective Income Tax Rate Reconciliation, Reduction, CARES Act, Percent Effective Income Tax Rate Reconciliation, Reduction, CARES Act, Percent Business Combination and Asset Acquisition [Abstract] Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Business Acquisition [Axis] Business Acquisition [Axis] Schedule of Capital Lease Obligations [Line Items] Schedule of Capital Lease Obligations [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Award Type [Domain] Award Type [Domain] Voting interest Variable Interest Entity, Qualitative or Quantitative Information, Voting Percentage Percentage of the Variable Interest Entity's voting interest owned by (or beneficial interest in) the reporting entity. Credit Facility [Domain] Credit Facility [Domain] Assets Assets [Abstract] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Stock Option Activity, Additional Disclosures Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] 2024 Long-Term Debt, Maturity, Year Three Number of options, exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Land Land [Member] Goodwill, accumulated impairment, beginning balance Goodwill, accumulated impairment, ending balance Goodwill, Impaired, Accumulated Impairment Loss Weighted average exercise price, expected to vest (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Interest Rate Swaps Derivative Instruments and Hedging Activities Disclosure [Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Concentration risk percentage Concentration Risk, Percentage Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Outstanding at beginning of period (in shares) Outstanding at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Entity Address, City or Town Entity Address, City or Town Retained Earnings Retained Earnings [Member] Debt Instrument [Axis] Debt Instrument [Axis] Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Total loan guaranteed Total Loan Guaranteed Represents the total amount of loan guaranteed. Advertising Costs Advertising Cost [Policy Text Block] COVID-19 Unusual or Infrequent Items, or Both, Disclosure [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Rental income (including $0.2 million and $0.0 associated with variable interest entity for the three months ended September 30, 2021 and 2020, respectively; and $0.7 million and $0.0 for the nine months ended September 30, 2021 and 2020, respectively, associated with variable interest entity) Rental income Rental Income, Nonoperating Ownership interest Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Subtotal 2 Long Term Debt Subtotal Two [Member] Subtotal 2 for long term debt. Accrued shipping expenses Accrued Shipping Expenses, Current Carrying value as of the balance sheet date of obligations incurred through that date and payable for shipping expenses. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Related Party [Axis] Related Party [Axis] Incentive Stock Optionee, Stock Ownership Greater than Ten Percent of Voting Power Incentive Stock Optionee Stock Ownership Greater Than Ten Percent Of Voting Power [Member] Incentive Stock Optionee, Stock Ownership Greater than Ten Percent of Voting Power [Member] Accounts receivable Increase (Decrease) in Accounts Receivable Capital expenditures funded by capital lease borrowings Capital Expenditures Incurred but Not yet Paid Inventories Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Business Combination, Goodwill [Abstract] Business Combination, Goodwill [Abstract] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Supplier [Axis] Supplier [Axis] Entity Interactive Data Current Entity Interactive Data Current Prime Rate Prime Rate [Member] Fixed interest rate Derivative, Fixed Interest Rate Basic (in dollars per share) Basic earnings per share (in dollars per share) Earnings Per Share, Basic Monthly lease payment Lessor Operating Lease Monthly Lease Payment Amount of monthly lease payment for operating lease. Outstanding at beginning of period (in shares) Outstanding at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Document Type Document Type 2022 Long-Term Debt, Maturity, Year One Summary of net sales disaggregated by customer type Disaggregation of Revenue [Table Text Block] Amortization of loan fees Amortization of Deferred Loan Origination Fees, Net Raw materials Inventory, Raw Materials, Gross Number of Shares Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Related party payable Increase (Decrease) in Due to Related Parties Entity Current Reporting Status Entity Current Reporting Status Machinery and equipment Machinery and Equipment [Member] Keary International Keary International [Member] Represents information pertaining to Keary International Ltd. Shares authorized (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Incentive program expenses Incentive Program Expenses Represents the amount of incentive program expenses which are reported as a contra to net sales. Provision for bad debt Accounts Receivable, Credit Loss Expense (Reversal) Notional amount, termination Derivative, Notional Amount, Termination Derivative, Notional Amount, Termination Long-term debt Long-term debt Long-term Debt, Gross Goodwill [Roll Forward] Goodwill [Roll Forward] Less inventory reserve Inventory Adjustments Level 1 Fair Value, Inputs, Level 1 [Member] Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Impairments of goodwill Impairment loss recognized Goodwill, Impairment Loss Document Transition Report Document Transition Report Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Computer hardware and software Software Development [Member] Long-term debt, net of current portion and debt discount of $0.2 million and $0.1 million at September 30, 2021 and December 31, 2020, respectively (including $35.6 million and $36.7 million associated with variable interest entity at September 30, 2021 and December 31, 2020, respectively, and debt discount of $0.2 million and $0.1 million associated with variable interest entity at September 30, 2021 and December 31, 2020, respectively) Long-term Debt, Excluding Long Term Line of Credit, Noncurrent Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding long term line of credit. Total liabilities and stockholders’ equity Liabilities and Equity Accrued expenses Other Accrued Liabilities, Current Pacific Cup, Inc Pacific Cup Inc [Member] Pacific Cup, Inc. [Member] Customer deposits (including $0.1 million and $0 million associated with variable interest entity at September 30, 2021 and December 31, 2020) Customer deposits Contract with Customer, Liability, Current 2025 Operating Leases, Future Minimum Payments, Due in Four Years Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Additional paid in capital Additional Paid in Capital Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Online Online [Member] Represents information pertaining to Online. Concentration Risk [Line Items] Concentration Risk [Line Items] Liabilities and Stockholders’ Equity Liabilities and Equity [Abstract] Term Loan, Maturing June 17, 2025 Term Loan Maturing June172025 [Member] Represents information pertaining to a Term Loan maturing June 17, 2025. Issuance of common stock in connection with initial public offering, net of issuance costs Proceeds from Issuance Initial Public Offering Accounts payable Increase (Decrease) in Accounts Payable Derivative [Line Items] Derivative [Line Items] Interest Rate Swap Interest Rate Swap [Member] Minimum bank account to make additional contributions from members Minimum Bank Account To Make Additional Contributions From Members Represents the minimum bank account to make additional contributions from members. Income Tax Contingency [Table] Income Tax Contingency [Table] Operating lease term Lessor, Operating Lease, Term of Contract Earnings Per Share Earnings Per Share [Text Block] Treasury stock acquired Treasury Stock, Value, Acquired, Cost Method Operating expenses: Operating Expenses [Abstract] Taizhou Fuling Plastics Co., Ltd Taizhou Fuling Plastics Co. Ltd [Member] Represents information pertaining to Taizhou Fuling Plastics Co.,Ltd. Standby letter of credit Standby Letters of Credit [Member] Minimum Minimum [Member] Government Grants Government Grants [Abstract] No definition available. Affiliated Entity Affiliated Entity [Member] Gross profit Gross Profit 2023 Operating Leases, Future Minimum Payments, Due in Two Years Balance Sheet Location [Domain] Balance Sheet Location [Domain] Debt Issuance Costs, Net Less: unamortized loan fees Debt Issuance Costs, Net Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Subsidiaries Subsidiaries [Member] Uncertain tax positions Unrecognized Tax Benefits Fair value Fair Value, Net Asset (Liability) Paycheck Protection Program, CARES Act Paycheck Protection Program, CARES Act [Member] Represents information pertaining to the Paycheck Protection Program loan. Floor rate Debt Instrument, Floor Rate Represents the floor rate on debt instrument. Distributors Distributors [Member] Represents information pertaining to Distributors. Equipment Loan With Draw Down Period Ending May 31, 2019 Equipment Loan With Draw Down Period Ending May312019 [Member] Represents information pertaining to an equipment loan with a draw down period ending May 31, 2019. Trading Symbol Trading Symbol Purchases Cost of Goods and Service, Product and Service Benchmark [Member] Deferred tax asset Deferred Income Tax Assets, Net Current liabilities Liabilities, Current [Abstract] 2025 Long-Term Debt, Maturity, Year Four Deferred rent liability Accrued Rent, Current Issuance of common stock in connection with our initial public offering, net of issuance costs of $5,088 Stock Issued During Period, Value, New Issues General and administrative expense (including $0.7 million and $0.8 million associated with variable interest entity for the three months ended September 30, 2021 and 2020, respectively; and $2.0 million and $1.4 million for the nine months ended September 30, 2021 and 2020, respectively, associated with variable interest entity) General and administrative expense General and Administrative Expense Fuling Technology Co., Ltd. Fuling Technology Co., Ltd. [Member] Fuling Technology Co., Ltd. Acquisition of Pacific Cup, Inc., net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Line of Credit Long-Term Debt Debt Disclosure [Text Block] Weighted average exercise price, exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Line of credit Line of Credit [Member] Stock-based Compensation Share-based Payment Arrangement [Text Block] Property, Plant and Equipment, Net, by Type [Abstract] Property, Plant and Equipment, Net, by Type [Abstract] Level 3 Fair Value, Inputs, Level 3 [Member] Dividends paid to shareholders Payments of Ordinary Dividends, Common Stock Inventories Inventory Disclosure [Text Block] Accounting Policies [Abstract] Accounting Policies [Abstract] Weighted average remaining contract life, options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Derivative Instrument [Axis] Derivative Instrument [Axis] Net of issuance costs Payments of Stock Issuance Costs Issuance of common stock in connection with our initial public offering, net of issuance costs of $5,088 (in shares) Stock Issued During Period, Shares, New Issues Reportable segment Number of Reportable Segments Accrued professional services fees Accrued Professional Fees, Current Loss on foreign currency transactions Loss of foreign currency transactions Foreign Currency Transaction Gain (Loss), before Tax Common stock, $0.001 par value, 100,000,000 shares authorized, 19,737,500 and 19,714,500 shares issued and outstanding, respectively, at September 30, 2021; 15,190,000 and 15,167,000 shares issued and outstanding, respectively, at December 31, 2020 Common Stock, Value, Issued Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total other income (expense) Nonoperating Income (Expense) Outstanding at beginning of period (in dollars per share) Outstanding at end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Acquired through business combination Goodwill, Acquired During Period Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Commitments and Contingencies (Note 13) Commitments and Contingencies Number of exercised convertible notes Number Of Exercised Convertible Notes Number Of Exercised Convertible Notes Payments to acquire treasury stock Treasury Stock, Value, Acquired, Par Value Method Subsequent Event [Table] Subsequent Event [Table] Ordinary share per dividend (in dollars per share) Dividends Payable, Amount Per Share Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Reserve for inventory obsolescence Inventory Write-down Acquisitions Business Combination Disclosure [Text Block] 2024 Operating Leases, Future Minimum Payments, Due in Three Years Foreign Currency Foreign Currency Transaction Gain (Loss), before Tax [Abstract] Document Period End Date Document Period End Date Stock options and restricted stock units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Entity Registrant Name Entity Registrant Name Cash and cash equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Treasury stock, shares (in shares) Treasury Stock, Shares Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Retail Retail [Member] Cumulative percentage ownership after all transactions Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions Cash consideration Payments to Acquire Productive Assets Prepaid expenses and other current assets (including $0.1 million and $0.1 million associated with variable interest entity at September 30, 2021 and December 31, 2020) Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Sales from related party Revenue from Related Parties Credit cards payable Increase (Decrease) in Credit Cards Payable The increase (decrease) during the period in the carrying value of credit cards payable. Accrued expenses (including $0.4 million and $0.1 million associated with variable interest entity at September 30, 2021 and December 31, 2020, respectively) Accrued expenses Total accrued expenses Accrued Liabilities, Current Net sales Revenue from Contract with Customer, Excluding Assessed Tax Accrued vacation and sick pay Accrued Vacation, Current (Increase) decrease in operating assets Increase (Decrease) in Operating Assets [Abstract] Share-based Payment Arrangement, Option Share-based Payment Arrangement, Option [Member] Term Loan, Maturing September 30, 2026 Term Loan Maturing September302026 [Member] Term Loan Maturing September302026 Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Derivative interest income Investment Income, Interest Common Stock Common Stock [Member] Variable Rate [Axis] Variable Rate [Axis] Operating income Operating Income (Loss) Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Stock-based compensation Share-based Payment Arrangement, Noncash Expense Variable Rate [Domain] Variable Rate [Domain] Additional Paid-in Capital Additional Paid-in Capital [Member] Cash and cash equivalents (including $0.7 million and $0.1 million associated with variable interest entity at September 30, 2021 and December 31, 2020) Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Depreciation and amortization expense Depreciation Cash and cash equivalents Cash and Cash Equivalents [Abstract] Treasury Stock Treasury Stock [Member] Accrued expenses Increase (Decrease) in Accrued Liabilities Summary of unvested restricted stock unit activity Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Proceeds from line of credit Proceeds from Lines of Credit Notional value Derivative, Notional Amount Business Combination and Goodwill Business Combinations And Goodwill [Policy Text Block] Disclosure of accounting policy regarding business combination and goodwill. Other liabilities Increase (Decrease) in Other Operating Liabilities Term loan, accordion feature Debt Instrument, Term Loan, Accordion Feature Debt Instrument, Term Loan, Accordion Feature Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Derivative fair value Derivative, Fair Value, Net Maximum Maximum [Member] Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Total liabilities Liabilities Summary of accrued expense liabilities Schedule of Accrued Liabilities [Table Text Block] Award Type [Axis] Award Type [Axis] Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Aggregate intrinsic value, options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Term Loan, Maturing July 2024 Term Loan Maturing July2024 [Member] Represents information pertaining to a Term Loan maturing July 2024. Total Karat Packaging Inc. stockholders’ equity Stockholders' Equity Attributable to Parent Common stock, shares issued (in shares) Common Stock, Shares, Issued Deposits relating to machinery and equipment Deposits Assets Relating to Machinery and Equipment Carrying value of amounts transferred to third parties for security purposes that are expected to be returned or applied towards payment in the future relating to machinery and equipment. Aggregate intrinsic value, exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Global Wells Global Wells [Member] Represents information pertaining to Global Wells. Gain on forgiveness of debt Gain on forgiveness of PPP loan Forgiveness of PPP loan Gain (Loss) on Extinguishment of Debt Schedule of estimated useful life of property and equipment Schedule of Property, Plant and Equipment, Useful Life [Table Text Block] Tabular disclosure of the useful life of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Variable Interest Entities Consolidation, Variable Interest Entity, Policy [Policy Text Block] Treasury stock acquired Payments for Repurchase of Common Stock Estimated useful life of property and equipment Property, Plant and Equipment, Useful Life Votes per share held Number Of Votes Per Common Stock And Preferred Stock Share Represents the number of votes per common or preferred stock. Supplemental disclosures of non-cash investing and  financing activities: Noncash Investing and Financing Items [Abstract] Concentration of Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Face amount of loan Debt Instrument, Face Amount Term Loan, Maturing May 31, 2024 Term Loan Maturing May312024 [Member] Represents information pertaining to a Term Loan maturing Mayr 31, 2024. Total assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net City Area Code City Area Code Retained earnings Retained Earnings (Accumulated Deficit) Lease term Lessee, Operating Lease, Term of Contract Unusual or Infrequent Items, or Both [Abstract] Unusual or Infrequent Items, or Both [Abstract] Award term Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Summary of assets acquired and liabilities assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Business Acquisition [Line Items] Business Acquisition [Line Items] Thereafter Operating Leases, Future Minimum Payments, Due After Four Years Operating Leases, Future Minimum Payments, Due After Four Years Income Statement [Abstract] Income Statement [Abstract] Amendment Flag Amendment Flag Concentration Risk [Table] Concentration Risk [Table] Keary Global and its affiliate, Keary International - related parties Keary Global And Its Affiliate Keary International Related Parties [Member] Represents information pertaining to Keary Global and its affiliate, Keary International, related parties. Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Payments on line of credit Repayments of Lines of Credit Debt discount Debt Instrument, Unamortized Discount, Noncurrent Canceled/forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Term of contract Derivative, Term of Contract Provision for income tax Income tax expense Income Tax Expense (Benefit) Total stockholders’ equity Balance at the beginning of period Balance at the end of period Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Accounts receivable, net of allowance for doubtful accounts of $0.3 million and $0.3 million at September 30, 2021 and December 31, 2020, respectively (including $0.0 and $0.0 million associated with variable interest entity at September 30, 2021 and December 31, 2020) Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Equity Components [Axis] Equity Components [Axis] Total current assets Assets, Current Selling expenses Selling and Marketing Expense [Member] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Inventories Total inventories Inventory, Net Entity File Number Entity File Number Stock-Based Compensation Share-based Payment Arrangement [Policy Text Block] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Other income Other Nonoperating Income Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Interest rates on capitalized leases Capital Lease Obligation, Interest Rate Represents the interest rates on capitalized leases. Schedule of Capital Lease Obligations [Table] Schedule of Capital Lease Obligations [Table] Schedule of capital lease obligation. Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Remaining stock-based compensation expense for unvested stock options Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Loan proceeds received Proceeds from Issuance of Unsecured Debt Debt, current portion (including $1.2 million and $0.7 million associated with variable interest entity at September 30, 2021 and December 31, 2020) Long-term debt, current portion Long-term debt, current portion Long-term Debt, Current Maturities Subtotal 1 Long Term Debt Subtotal One [Member] Subtotal 1 for long term debt. Product and Service [Axis] Product and Service [Axis] Long-Lived Tangible Asset [Domain] Long-Lived Tangible Asset [Domain] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Small Business Entity Small Business Equipment Loan, Draw Down Period Ending August 28, 2019 Equipment Loan With Draw Down Period Ending August282019 [Member] Represents information pertaining to an equipment loan with a draw down period ending August 28, 2019. Remaining stock-based compensation expense for unvested restricted stock units Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Equity Component [Domain] Equity Component [Domain] Transfers from deposit to property and equipment Property, Plant and Equipment, Transfers and Changes Entity Ex Transition Period Entity Ex Transition Period Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Debt issuance costs Debt Issuance Costs, Gross Vehicles Vehicles [Member] Statement [Line Items] Statement [Line Items] Line of credit Long-term Line of Credit, Noncurrent Stockholder's Equity Stockholders' Equity, Policy [Policy Text Block] Customer deposits Increase (Decrease) in Contract with Customer, Liability Assets and Liabilities, Lessee [Abstract] Assets and Liabilities, Lessee [Abstract] Total number of shares of all classes of stock authorized (in shares) Shares Authorized Represents the total number of shares of all classes of stock authorized. Weighted- Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Acquisition of Pacific Cup, Inc. included within deposits Acquisition Price Included Within Deposits Represents the acquisition price included within deposits in noncash or partial noncash transaction. Counterparty Name [Domain] Counterparty Name [Domain] Future minimum lease obligations Operating Leases, Future Minimum Payments Due Debt Disclosure [Abstract] Debt Disclosure [Abstract] Entity Address, State or Province Entity Address, State or Province Capital leases, current portion Finance Lease, Liability, Current Income before provision for income tax Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Level 2 Fair Value, Inputs, Level 2 [Member] Long-Lived Tangible Asset [Axis] Long-Lived Tangible Asset [Axis] Deposits Increase (Decrease) in Deposit Assets Keary Global Keary Global Ltd [Member] Represents information pertaining to Keary Global Ltd. Change in fair value of interest rate swap Derivative, Gain (Loss) on Derivative, Net 2022 Operating Leases, Future Minimum Payments Due, Next Twelve Months Estimates and Assumptions Use of Estimates, Policy [Policy Text Block] Schedule of earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Granted (in shares) Options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Entity Shell Company Entity Shell Company Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Local Phone Number Local Phone Number Total assets Assets Investment, Name [Domain] Investment, Name [Domain] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Geographical [Domain] Geographical [Domain] Accrued Expenses Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Product and Service [Domain] Product and Service [Domain] Noncontrolling Interest Noncontrolling Interest [Member] Thereafter Long-Term Debt, Maturity, After Year Four Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing after fourth fiscal year following current fiscal year. Cumulative grants Government Grants The amount of government grants received as of balance sheet date. Fixed interest rate Debt Instrument, Interest Rate, Stated Percentage Derivative Contract [Domain] Derivative Contract [Domain] Maximum borrowing capacity Debt Instrument, Maximum Borrowing Capacity Maximum borrowing capacity under the terms of the debt instrument without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding. Net income (loss) attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Stock-based Compensation Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Measurement Frequency [Axis] Measurement Frequency [Axis] Net cash (used in) provided by operating activities Net Cash Provided by (Used in) Operating Activities Deposits Deposits [Policy Text Block] Disclosure of accounting policy regarding deposits. Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Furniture and fixtures Furniture and Fixtures [Member] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Entity Tax Identification Number Entity Tax Identification Number Subsequent Event [Line Items] Subsequent Event [Line Items] Proceeds from long-term debt, net of issuance cost Proceeds from Issuance of Long-term Debt, Excluding Proceeds From Long Term Line of Credit The cash inflow from a debt excluding line of credit initially having maturity due after one year or beyond the operating cycle, if longer. Geographical [Axis] Geographical [Axis] Number of primary shareholders Number Of Primary Shareholders Number Of Primary Shareholders Weighted average common shares outstanding, basic (in shares) Weighted average number of common shares in issue (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in dollars per share) Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Dilutive shares Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Related party payable Due to Lollicup USA Inc. Due to Related Parties, Current Cash paid for income tax Income Taxes Paid, Net Supplier [Domain] Supplier [Domain] Purchases from related party Related Party Costs Subsequent Events Subsequent Events [Text Block] Accrued payroll Accrued Payroll Taxes, Current New Jersey NEW JERSEY Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Treasury stock, $0.001 par value, 23,000 and 23,000 shares on September 30, 2021 and December 31, 2020, respectively Treasury Stock, Value Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted Average Number of Shares Outstanding, Diluted [Abstract] Deferred tax liability Deferred Income Tax Liabilities, Net Related Party Transaction [Line Items] Related Party Transaction [Line Items] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Promissory Note Promissory Note [Member] Represents information pertaining to a promissory note. Other Liabilities Other Noncurrent Liabilities [Member] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Property and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Contributions to offset the amount that member cannot contribute (up to) Contributions To Offset The Amount That Member Cannot Contribute Represents the contributions to offset the amount that member cannot contribute. Amount converted to term loan Debt Conversion, Amount Converted To New Debt Instrument This amount represent the amount converted to term loan Other unrelated parties Number of Other Unrelated Parties Represents the number of other unrelated parties. VIE, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Accounts payable (including $0.0 million and $0.6 million associated with variable interest entity at September 30, 2021 and December 31, 2020, respectively) Accounts payable Accounts Payable, Current Concentration Risk Type [Axis] Concentration Risk Type [Axis] Lollicup Franchising, LLC Lollicup Franchising Llc [Member] Lollicup Franchising, LLC [Member] Depreciation and amortization Depreciation, Depletion and Amortization Total Stockholders’ Equity attributable to Karat Packaging Inc. Parent [Member] Interest rate swaps Interest Rate Derivative Liabilities, at Fair Value Summary of fair value measurements by level for the assets and liabilities measured at fair value on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of variable interest entity financial information Schedule of Variable Interest Entities [Table Text Block] Inventories Increase (Decrease) in Inventories Cash dividends Dividends Payable Common stock, shares outstanding (in shares) Balance at the beginning of period (in shares) Balance at the end of period (in shares) Common Stock, Shares, Outstanding Supplier Supplier Concentration Risk [Member] 2021 (remainder) Operating Leases, Future Minimum Payments, Remainder of Fiscal Year Derivative [Table] Derivative [Table] Cost of goods sold Cost of Goods and Services Sold Issuance of common stock upon vesting of restricted stock units (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Reporting unit Number of Reporting Units Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Texas TEXAS Number of Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Consolidated Entities [Domain] Consolidated Entities [Domain] Schedule of property and equipment, net Property, Plant and Equipment [Table Text Block] Income Statement Location [Domain] Income Statement Location [Domain] Effect on initial consolidation of Lollicup Franchising Inc, net of cash acquired Payments To Acquire Lollicup Franchising Inc, Effect On Initial Consolidation, Net of Cash Acquired Payments To Acquire Lollicup Franchising Inc, Effect On Initial Consolidation, Net of Cash Acquired Karat Packaging Inc. stockholders’ equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Number of non-employee directors and employees Number Of Non-Employee Directors And Employees Number Of Non-Employee Directors And Employees Property and equipment, net (including $46.9 million and $47.8 million associated with variable interest entity at September 30, 2021 and December 31, 2020, respectively) Property and equipment, net Total property and equipment, net Property, Plant and Equipment, Net Property and Equipment Property, Plant and Equipment Disclosure [Text Block] Total operating expenses Operating Expenses Other liabilities (including $2.9 million and $3.9 million associated with variable interest entity at September 30, 2021 and December 31, 2020, respectively) Other liabilities Other Liabilities, Noncurrent Schedule of long-term debt Schedule of Long-term Debt Instruments [Table Text Block] Treasury stock acquired (in shares) Treasury stock acquired (in shares) Treasury Stock, Shares, Acquired Debt Instrument [Line Items] Debt Instrument [Line Items] Payments on long-term debt Repayments of Long-term Debt Basic and diluted earnings per share: Earnings Per Share [Abstract] Accounts payable Accounts Payable [Member] Property and equipment, gross Property, Plant and Equipment, Gross Subtotal Inventory, Gross Document Quarterly Report Document Quarterly Report Schedule of future minimum lease obligations Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Other assets Increase (Decrease) in Other Operating Assets Number of options, expected to vest (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Line of Credit Facility [Table] Line of Credit Facility [Table] Finished goods Inventory, Finished Goods, Gross Deposits [Abstract] Deposits [Abstract] Outstanding at beginning of period (in dollars per share) Outstanding at end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Long-term debt, net of current portion Long-term Debt, Excluding Current Maturities Maximum exposure to loss Variable Interest Entity, Primary Beneficiary, Maximum Loss Exposure, Amount Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Term Loan, Maturing June 30, 2025 Term Loan Maturing June302025 [Member] Represents information pertaining to a Term Loan maturing June 30, 2025. Stock-based compensation expense Share-based Payment Arrangement, Expense Weighted average remaining contract life, exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Term Loan, Maturing May 2029 Term Loan Maturing May2029 [Member] Represents information pertaining to a Term Loan maturing May 2029. Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Effective tax rate Effective Income Tax Rate Reconciliation, Percent Net income Net income (loss) Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Counterparty Name [Axis] Counterparty Name [Axis] Payables and Accruals [Abstract] Payables and Accruals [Abstract] Beginning of year End of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Term Loan, Maturing December 31, 2021 Term Loan Maturing December312021 [Member] Represents information pertaining to a Term Loan maturing December 31, 2021. Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Schedule of concentration of credit risk Schedules of Concentration of Risk, by Risk Factor [Table Text Block] Current assets Assets, Current [Abstract] Shares reserved for issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Interest expense (including $0.3 million and $0.3 million associated with variable interest entity for the three months ended September 30, 2021 and 2020, respectively; and $0.3 million and $2.9 million for the nine months ended September 30, 2021 and 2020, respectively, associated with variable interest entity) Interest income (expense) Interest income (expense) Interest Income (Expense), Nonoperating, Net Deposits paid for property and equipment Payments For Deposits For Property, Plant And Equipment The cash outflow associated with the deposits of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Entity Central Index Key Entity Central Index Key Income Taxes Income Tax, Policy [Policy Text Block] Impairment of Long-lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Security Exchange Name Security Exchange Name Term Loan, Maturing April 30, 2021 Term Loan Maturing April302021 [Member] Represents information pertaining to a Term Loan maturing April 30, 2021. Increase (decrease) in operating liabilities Increase (Decrease) in Operating Liabilities [Abstract] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Payments on capital lease obligations Payments on capital lease obligations Repayments of Long-term Capital Lease Obligations Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Weighted average common shares outstanding, diluted (in shares) Adjusted weighted average number of common shares (in shares) Weighted Average Number of Shares Outstanding, Diluted Selling expense Selling Expense Recurring basis Fair Value, Recurring [Member] Income Taxes Income Tax Disclosure [Text Block] Accrued interest Interest Payable, Current Accelerated award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Accelerated Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Earlier Than Original Vesting Date, Award Vesting Period, Related Party [Domain] Related Party [Domain] Current Fiscal Year End Date Current Fiscal Year End Date Summary of stock option activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Spread on variable rate Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Government Grants Government Grants [Policy Text Block] Disclosure of accounting policy regarding government grants. Term Loan, Maturing March 2023 Term Loan Maturing March2023 [Member] Represents information pertaining to a Term Loan maturing March 2023. Derivative interest expense Investment Income, Investment Expense Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Other income (expense) Nonoperating Income (Expense) [Abstract] Credit Facility [Axis] Credit Facility [Axis] Maximum advances (up to) Advances to Affiliate Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Less accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Interest rate during the period Debt Instrument, Interest Rate During Period Number of primary stockholders who guaranteed loans Number of Variable Interest Entities Who Guaranteed Loans Represents the number of variable interest entities who guaranteed loans. Principles of Consolidation Consolidation, Policy [Policy Text Block] Total current liabilities Liabilities, Current Due from affiliated companies Increase (Decrease) in Due from Related Parties, Current Accumulated impairment Goodwill, Impaired, Accumulated Impairment Loss [Abstract] Maximum borrowing Line of Credit Facility, Maximum Borrowing Capacity Aggregate intrinsic value, expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Entity Address, Postal Zip Code Entity Address, Postal Zip Code Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Title of 12(b) Security Title of 12(b) Security Wen Ho Industrial Co. Wen Ho Industrial Co. [Member] Wen Ho Industrial Co. Statement [Table] Statement [Table] Advertising costs Advertising Expense New and Recently Adopted Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Statistical Measurement [Axis] Statistical Measurement [Axis] Accounts Receivable and Allowance for Doubtful Accounts Accounts Receivable [Policy Text Block] Noncontrolling Interests Noncontrolling Interests [Policy Text Block] Disclosure of accounting policy regarding noncontrolling interests. Subsequent Event Subsequent Event [Member] Major shareholders who share common ownership with Lollicup Franchising Number Of Major Shareholders Who Share Common Ownership With Lollicup Franchising Represents the number of major shareholders who share common ownership. Cover [Abstract] Cover [Abstract] Deposits Deposits Assets, Noncurrent Capital leases, net of current portion Finance Lease, Liability, Noncurrent Goodwill Goodwill, beginning balance Goodwill, ending balance Goodwill Store owned Number Of Store Owned Represents the number of store owned. Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest Income taxes payable Accrued Income Taxes, Current Inventories Inventory, Policy [Policy Text Block] Schedule of goodwill Schedule of Goodwill [Table Text Block] Nature of Operations Nature of Operations [Text Block] Adjustments to reconcile net income to net cash (used in) provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Related Party Transactions Related Party Transactions Disclosure [Text Block] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Monthly lease payment Operating Leases, Rent Expense Stock-based compensation expense, increase Share-based Payment Arrangement, Expense, Increase Share-based Payment Arrangement, Expense, Increase Monthly principal and interest payments Debt Instrument, Periodic Payment Weighted average remaining contract life, expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term