Document And Entity Information Statistical Measurement [Axis] Note To Financial Statement Details Textual Document Fiscal Period Focus EBP, Basis of Accounting [Policy Text Block] EBP, Note Receivable from Participant [Policy Text Block] Significant Accounting Policies Document Fiscal Year Focus us-gaap-ebp_EmployeeBenefitPlanDebtInterestRate EBP, Debt, Interest Rate Note 4 - Fair Value Measurements Note 7 - Reconciliation of Financial Statements to Schedule H of Form 5500 EBP, Net Asset Available for Benefit [Abstract] Schedule H, Line 4(i) Amendment Flag senea_PolicyTable Note 4 - Fair Value Measurements - Schedule of Fair Value Hierarchy (Details) Net assets available for benefits per the Form 5500 Note 7 - Reconciliation of Financial Statements to Schedule H of Form 5500 - Schedule of Net Assets Available for Benefits (Details) us-gaap-ebp_EmployeeBenefitPlanAssetHeldForInvestmentPartyInInterest EBP, Asset Held for Investment, Party-in-Interest [true false] Schedule H, Line 4(i) - Schedule of Assets (Held at End of Year) (Details) Schedule H, Line 4(i) - Schedule of Assets (Held at End of Year) 2 (Details) Notes To Financial Statements Minimum [Member] Notes To Financial Statements [Abstract] dei_DocumentPeriodEndDate Document Period End Date Statistical Measurement [Domain] us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitIncreaseForContribution Total contributions Maximum [Member] Legal Entity [Axis] Other income Amount of other income in net asset available for benefit from contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). EBP, Schedule of Asset Held for Investment [Table] EBP 16-0733425 003 [Member] Represents EBP 16-0733425 003 senea_EBPTerminationVestedBalanceToCashOut EBP, Termination Vested Balance to Cash Out Amount of vested balance at termination to cash out in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Seneca Foods Corporation Employer Stock Fund [Member] Represents the Seneca Foods Corporation Employer Stock Funds. Total Assets in the Fair Value Hierarchy [Member] Represents total assets in the fair value hierarchy. Notes receivable from participants Notes receivable from participants dei_EntityTaxIdentificationNumber Entity Tax Identification Number EBP, Investment, Fair Value and NAV [Text Block] Entity [Domain] Entity Central Index Key Net appreciation in fair value of investments dei_EntityRegistrantName Entity Registrant Name Variable Annuities [Member] Variable Annuities Entity Current Reporting Status EBP, Description of Plan [Text Block] us-gaap-ebp_EmployeeBenefitPlanAssetHeldForInvestment EBP, Asset Held for Investment EBP, Related Party and Party-in-Interest Transactions [Table] Non-pension Plan [Member] Non-pension Plan Current Fiscal Year End Date us-gaap-ebp_EmployeeBenefitPlanTaxDeterminationLetterDate EBP, Tax Determination Letter, Date Investments Measured at Net Asset Value [Member] Represents Investments Measured at Net Asset Value. us-gaap-ebp_EmployeeBenefitPlanAssetHeldForInvestmentParticipantLoanAfterDeemedDistribution EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitIncrease Total Fair Value Measured at Net Asset Value Per Share [Member] Entity Shell Company Common Collective Trust [Member] Entity Emerging Growth Company Entity Small Business Investments [Domain] Benefits paid to participants Accounting Policies [Abstract] Rollovers us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitIncreaseForEmployerContribution EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash EBP, Risk and Uncertainty [Table] us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitIncreaseDecreaseForIncomeLossOnInvestment Total investment income Pension Plan 401 (k) [Member] Represents 401 (k) pension plan. EBP, Accounting Standard Update and Change in Accounting Principle [Table] Fully-benefit responsive investment contracts, at contract value us-gaap-ebp_EmployeeBenefitPlanTaxQualificationStatusExtensibleEnumeration EBP, Tax Qualification Status [Extensible Enumeration] Valuation Approach and Technique [Domain] Valuation, Market Approach [Member] Statement of Stockholders' Equity [Abstract] EBP, Tax Status [Text Block] us-gaap-ebp_EmployeeBenefitPlanInvestmentFairAndContractValue Total investments us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccount EBP, Forfeited Nonvested Account us-gaap-ebp_EmployeeBenefitPlanInvestmentValuationTechniqueExtensibleEnumeration EBP, Investment, Valuation Technique [Extensible Enumeration] us-gaap-ebp_EmployeeBenefitPlanAssetHeldForInvestmentInvestmentExcludingPlanInterestInMasterTrustCurrentValue EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value EBP, Reconciliation of Financial Statement to Form 5500 [Table Text Block] Equity Components [Axis] Class of Stock [Axis] Equity Component [Domain] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Interest and dividend income us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAllowanceForCreditLoss EBP, Note Receivable from Participant, Allowance for Credit Loss Fair Value, Inputs, Level 1 [Member] Investments us-gaap-ebp_EmployeeBenefitPlanReconciliationToForm5500NetAssetAvailableForBenefitContractValueToCurrentValueAdjustment us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitIncreaseDecrease Net increase in net assets available for benefits EBP, Subsequent Event [Table] EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] EBP, Reconciliation of Financial Statement to Form 5500 [Text Block] us-gaap-ebp_EmployeeBenefitPlanParticipantLoanInterestRate EBP, Asset Held for Investment, Participant Loan, Interest Rate Subsequent Event [Member] us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccountDecreaseForEmployerContribution EBP, Forfeited Nonvested Account, Decrease from Employer Contribution EBP, Participant-Directed [Member] EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Subsequent Event Type [Domain] Subsequent Event Type [Axis] EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Financial assets: Investments, at fair value EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value us-gaap-ebp_EmployeeBenefitPlanInvestmentExcludingPlanInterestInMasterTrustContractValue EBP, Investment, Excluding Plan Interest in Master Trust, Contract Value Employer Administration expenses Investments: Investment, Identifier [Axis] Receivables: EBP, Description of Plan [Table] us-gaap-ebp_EmployeeBenefitPlanReceivable Total receivables Statement [Table] EBP, Reconciliation of Financial Statement to Form 5500 [Table] EBP, Tax Status [Table] Fair Value Hierarchy and NAV [Domain] us-gaap-ebp_EmployeeBenefitPlanPlanNumber EBP, Plan Number EBP, Risk and Uncertainty [Text Block] Statement of Financial Position [Abstract] us-gaap-ebp_EmployeeBenefitPlanFullyBenefitResponsiveInvestmentContractDescription EBP, Fully Benefit-Responsive Investment Contract, Description Variable Annuity [Member] EBP, Fully Benefit-Responsive Investment Contract [Text Block] senea_EBPFullyBenefitResponsiveInvestmentContractCreditingRate EBP, Fully Benefit-Responsive Investment Contract, Crediting Rate Percentage for crediting rate of fully benefit-responsive investment contract held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). us-gaap-ebp_EmployeeBenefitPlanInvestmentTypeExtensibleEnumeration EBP, Investment, Current Value, Type [Extensible Enumeration] EBP, Participant-Directed and Nonparticipant-Directed Status [Domain] us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate EBP, Participant Contribution, Automatic, Deferral Rate Investment Type [Axis] us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage EBP, Employer Contribution, Matching Percentage Mutual Fund [Member] EBP, Schedule of Asset Held for Investment [Text Block] EBP, Use of Estimate [Policy Text Block] EBP, Subsequent Event [Text Block] us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingAmount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingAmount EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount EBP, Expense [Policy Text Block] Schedule Of Assets [Text Block] The entire disclosure for schedule of assets. us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationToTotalCompensationPercentage EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage EBP, Related Party and Party-in-Interest [Domain] EBP, Employer, Common Stock Fund [Member] dei_DocumentType Document Type Common Collective Trusts [Member] Common Collective Trusts. EBP, Summary of Accounting Policy [Text Block] Document Information [Line Items] EBP, Investment [Policy Text Block] Employer's contribution Document Information [Table] Entity Interactive Data Current us-gaap-ebp_EmployeeBenefitPlanForm5500CaptionTransferToFromPlan EBP, Form 5500 Caption, Transfers of Assets to (from) this Plan Statement [Line Items] Fair Value Hierarchy and NAV [Axis] EBP, Related Party and Party-in-Interest [Axis] EBP, Payment to Participant [Policy Text Block] us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingToTotalAccountPercentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage us-gaap-ebp_EmployeeBenefitPlanEmployerContributionParticipantCompensationMatchedPercentage EBP, Employer Contribution, Participant Compensation Matched, Percentage us-gaap-ebp_EmployeeBenefitPlanTaxDeterminationLetterObtained EBP, Tax Determination Letter, Obtained [true false] us-gaap-ebp_EmployeeBenefitPlanAssetHeldForInvestmentInvestmentExcludingPlanInterestInMasterTrustParticipationStatusExtensibleEnumeration EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] us-gaap-ebp_EmployeeBenefitPlanChangeInNetAssetAvailableForBenefitDecrease Total Fixed Income Funds [Member] EBP, Related Party and Party-in-Interest Transactions [Text Block] EBP, Plan Termination [Text Block] Assets Net assets available for benefits per the financial statements Net assets available for benefits Beginning of year End of year EBP, Fully Benefit-Responsive Investment Contract [Table] EBP, Investment, Fair Value and NAV [Table Text Block] us-gaap_PolicyTextBlockAbstract Accounting Policies Participants EBP, Investment, Fair Value and NAV [Table] us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements Retirement Plan Tax Status [Domain] us-gaap_TableTextBlock Notes Tables Qualified Plan [Member]