Document And Entity Information Statistical Measurement [Axis] Note To Financial Statement Details Textual Significant Accounting Policies Income taxes Income taxes Total income taxes Note 1 - Summary of Significant Accounting Policies Note 2 - Revenue Recognition Restricted cash us-gaap_RestrictedCashAndCashEquivalents Note 3 - Earnings Per Share Note 4 - Inventories Retirement Benefits [Text Block] Note 5 - Property, Plant and Equipment Note 6 - Debt Note 7 - Leases Note 8 - Income Taxes Note 10 - Retirement Plans Minimum [Member] Note 12 - Fair Value of Financial Instruments Note 13 - Segment Information Statistical Measurement [Domain] Note 16 - Acquisition Maximum [Member] Manufactured Product, Other [Member] Schedule II - Valuation and Qualifying Accounts Note 1 - Summary of Significant Accounting Policies - Schedule of Cash and Cash Equivalents (Details) Cost of Goods and Service, Product and Service Benchmark [Member] Note 1 - Summary of Significant Accounting Policies - Estimated Useful Lives (Details) Retirement Plan Name [Domain] Note 2 - Revenue Recognition - Segment Revenue Disaggregated by Product Category Groups (Details) us-gaap_IncreaseDecreaseInAccountsReceivable Accounts receivable Note 2 - Revenue Recognition - Summary of Deferred Revenue Activity (Details) Retirement Plan Type [Domain] Note 3 - Earnings Per Share - Earnings Per Share (Details) Retirement Plan Name [Axis] Note 4 - Inventories - Inventories by Category and Impact of Using LIFO Method (Details) Note 5 - Property, Plant and Equipment - Property, Plant and Equipment (Details) Retirement Plan Type [Axis] Note 6 - Debt - Schedule of Debt Maturities (Details) Note 6 - Debt - Summary of Long-term Debt (Details) us-gaap_EffectOfLIFOInventoryLiquidationOnIncome Effect of LIFO Inventory Liquidation on Income us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses Amortization of net loss Note 6 - Debt - Summary of Revolver Borrowings (Details) Amortization of prior service cost Note 7 - Leases - Lease Expense (Details) Schedule of Valuation and Qualifying Accounts [Table Text Block] Tabular disclosure for valuation and qualifying accounts and reserves. Note 7 - Leases - Undiscounted Future Lease Payments Under Operating Leases and Financial Leases (Details) Note 8 - Income Taxes - Provision of Income Taxes (Details) us-gaap_InterestCostsCapitalized Interest Costs Capitalized us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation Defined Benefit Plan, Accumulated Benefit Obligation Note 8 - Income Taxes - Reconciliation of Income Tax Rate (Details) Actual return on plan assets us-gaap_DefinedBenefitPlanBenefitObligationPeriodIncreaseDecrease Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease) Note 8 - Income Taxes - Cash Paid for Income Taxes (Details) Note 8 - Income Taxes - Deferred Income Tax Assets and Liabilities (Details) Note 8 - Income Taxes - Uncertain Tax Positions (Details) Note 10 - Retirement Plans - Statement of Unfunded Status (Details) State rate changes us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate Note 10 - Retirement Plans - Amounts Recognized in Accumulated Other Comprehensive (Details) us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance Change in valuation allowance Counterparty Name [Axis] Note 10 - Retirement Plans - Net Periodic Benefit Cost (Details) us-gaap_EffectiveIncomeTaxRateContinuingOperations Total, percent Customer A [Member] Relating to customer A. Note 10 - Retirement Plans - Other Changes in Plan Assets and Benefit Obligation (Details) Note 10 - Retirement Plans - Assumptions Used to Measure (Details) senea_EffectOfLIFOInventoryLiquidationOnCostOfSales Effect of LIFO Inventory Liquidation on Cost of Sales Represents the effect LIFO inventory liquidation on cost of sales. us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate U.S federal statutory rate, percent Note 10 - Retirement Plans - Estimated Future Benefit Payments (Details) Lump Sum Payout [Member] Relating to lump sum payout. Note 10 - Retirement Plans - Schedule of Allocation of Plan Assets (Details) Note 10 - Retirement Plans - Fair Value of Plan Assets (Details) Note 12 - Fair Value of Financial Instrument - Fair Value and Carrying Value of Long-term Debt (Details) us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease Defined Benefit Plan, Plan Assets, Period Increase (Decrease) Note 13 - Segment Information - Segment Information (Details) Note 13 - Segment Information - Schedule of Revenue by Geographic Area (Details) Note 16 - Acquisition - Allocation of Purchase Price of Acquisition (Details) Note 16 - Acquisition - Pro Forma Information (Details) Food Packaging [Member] Information by product and service, or group of similar products and similar services. Schedule II - Valuation and Qualifying Accounts - Schedule of Valuation and Qualifying Accounts (Details) Notes To Financial Statements Notes To Financial Statements [Abstract] Discount rate - projected benefit obligation us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate Land Improvements [Member] Interest cost Deduct preferred stock dividends Funded status Plan Assets, Amount Defined Benefit Plan, Plan Assets, Amount Fair value of plan assets at beginning of year Fair value of plan assets at end of year us-gaap_DividendsPreferredStockCash Cash dividends declared on preferred stock Dividends, Preferred Stock, Cash us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets Expected return on plan assets Changes in unrecognized tax benefits, percent State income taxes (net of federal tax benefit) us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes State income taxes (net of federal tax benefit) (1), percent us-gaap_IncreaseDecreaseInInventories Inventories Counterparty Name [Domain] Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax Net loss Service cost (excluding expenses) Rate of compensation increase us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease us-gaap_PreferredStockDividendRatePercentage Preferred Stock, Dividend Rate, Percentage Letter of Credit [Member] Contribution of 401(k) match Defined Benefit Plan, Equity Securities [Member] Segment Reporting [Text Block] Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Domain] us-gaap_DefinedBenefitPlanBenefitObligation Defined Benefit Plan, Benefit Obligation Benefit obligation at beginning of year Benefit obligation at end of year us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetTransitionAssetsObligationsBeforeTax Prior service cost Adjustments to reconcile net earnings to net cash from operating activities: Segment Reporting [Table Text Block] Preferred stock us-gaap_Liabilities Total liabilities Defined Benefit Plan [Table] State depreciation basis differences Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from State depreciation basis differences. us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and stockholders’ equity Consolidation Items [Axis] State return to accrual Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state return to accrual. senea_DeferredTaxAssetsOperatingLeases Operating leases Amount of deferred tax liability attributable to taxable temporary differences from operating leasing arrangements. Segment Reporting [Table] Selling and advertising expense us-gaap_SellingAndMarketingExpense Selling, general, and administrative expense Stock-based compensation expense Subsequent Event [Member] Consolidation Items [Domain] Amended Term Loan A-2 [Member] Represents information on the Amended Term Loan A-2 payable to Farm Credit East ACA. us-gaap_IncreaseDecreaseInAccountsPayable Accounts payable Second Amended and Restated Loan and Guaranty Agreement Amendment One with Farm Credit East, ACA [Member] Represents information related to the Second Amended and Restated Loan and Guaranty Agreement Amendment 1 with Farm Credit East, ACA. Preferred stock, shares outstanding (in shares) us-gaap_PreferredStockSharesOutstanding Preferred Stock, Shares Outstanding (in shares) Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Series B Preferred Stock [Member] Fair Value, by Balance Sheet Grouping [Table] us-gaap_PreferredStockParOrStatedValuePerShare Preferred Stock, Par or Stated Value Per Share (in dollars per share) Restricted cash us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect Net (decrease) increase in cash, cash equivalents and restricted cash us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents Total cash, cash equivalents and restricted cash Unfunded Deferred Compensation Plan [Member] Represents information on the unfunded deferred compensation plan. Series A Preferred Stock [Member] New Accounting Pronouncements, Policy [Policy Text Block] Lessor, Lease, Description [Table] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations Cash, cash equivalents and restricted cash, beginning of the period Cash, cash equivalents and restricted cash, end of the period Concentration Risk, Credit Risk, Policy [Policy Text Block] Comprehensive income: Statement [Table] Credit Facility [Axis] Operating cash flows from operating leases Credit Facility [Domain] Revolving Credit Facility [Member] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Domain] senea_ContractWithCustomerLiabilityDeduction Recognition of unearned revenue Amount of deduction of contract with customer liability. Term Loan A-2 [Member] Represents information for Term Loan A-2. us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 Debt Instrument, Basis Spread on Variable Rate Right-of-use assets obtained in exchange for new operating lease obligations us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets Intangibles senea_ContractWithCustomerLiabilitySettlement Settlement of liability Amount of settlement of contract with customer liability. Deferral of revenue Amount of addition to the balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. Right-of-use assets obtained in exchange for new finance lease obligations Term Loan A-1 [Member] Represents information for Term Loan A-1. Financing cash flows from finance leases Payments on finance leases Cumulative Convertible Preferred Stock [Member] Preferred stock that may be exchanged into common shares or other types of securities at the owner's option and which unpaid dividends accumulate until paid to shareholders. us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity Beneficiaries of Former Employees That Have Family Relationships to Two of Current Directors [Member] Represents Beneficiaries of Former Employees That Have Family Relationships to Two of Current Directors. Average outstanding borrowings Retirement Arrangements [Member] Retirement Arrangements. Interest rate Maximum amount of borrowings drawn during the period New York State Division of Taxation and Finance [Member] Nature of Operations, Policy [Policy Text Block] Disclosure of accounting policy for the Nature of Operations. us-gaap_LineOfCreditFacilityInterestRateDuringPeriod Weighted average interest rate us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity Line of Credit Facility, Remaining Borrowing Capacity Long-Term Debt, Type [Axis] Surety Bond [Member] Employees’ Savings 401(k) Plan [Member] Represents information on the employees’ savings 401(k) plans. Product and Service [Domain] Product and Service [Axis] Revolving credit facility Outstanding borrowings Long-Term Line of Credit Useful life (Year) Participating Convertible Preferred Stock [Member] Participating peferred stock that may be exchanged into common shares or other types of securities at the owner's option. senea_LineOfCreditFacilityMaximumBorrowingCapacityDuringNonproductionPeriod Line of Credit Facility, Maximum Borrowing Capacity During Nonproduction Period Maximum borrowing capacity under the credit facility during the reporting entity's nonproduction period without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. Thereafter us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive Term Loan [Member] Represents the term loan. us-gaap_RepaymentsOfDebt Repayments of Debt us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Total minimum payment required, operating Diversified Mix of Return-seeking Investments [Member] Diversified Mix of Return-seeking Investments. Fixed Income Investment [Member] Fixed Income Investment. Office Furniture, Vehicles and Computer Software [Member] Office Furniture, Vehicles and Computer Software. State credit expiration Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state credit expiration. Finance leases, discount rate Operating leases, discount rate 2027, operating Property, Plant and Equipment, Useful Life [Table Text Block] Tabular disclosure of the useful life of physical assets used in the normal conduct of business and not intended for resale. Thereafter, operating us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive Defined Benefit Plan, Other [Member] Defined Benefit Plan, Other. Defined Benefit Plan, Equity Securities Held in Common Collective Trusts [Member] Defined Benefit Plan, Equity Securities Held in Common Collective Trusts. Defined Benefit Plan, Real Estate Held in Common Collective Trusts [Member] Defined Benefit Plan, Real Estate Held in Common Collective Trusts. Schedule of Maturities of Long-Term Debt [Table Text Block] Defined Benefit Plan, Debt Security Held in Common Collective Trusts [Member] Defined Benefit Plan, Debt Security Held in Common Collective Trusts. Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts [Member] Defined Benefit Plan, Cash and Short-term Investments Held in Common Collective Trusts. 2029, operating us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree 2028, operating us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo Statement [Line Items] Business interest limitation 2030, operating us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour Fair Value Hierarchy and NAV [Axis] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Common stock, shares outstanding (in shares) us-gaap_CommonStockSharesOutstanding Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Common stock, shares authorized (in shares) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Common Class B [Member] Common stock Assets acquired from exercise of finance lease purchase options, net of accumulated depreciation us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostChangeDueToSubsequentInterimMeasurementWeightedAverageExpectedLongTermRateOfReturnOnPlanAssets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Change Due to Subsequent Interim Measurement, Weighted-Average Expected Long-Term Rate of Return on Plan Assets Fair Value of Financial Instruments, Policy [Policy Text Block] Amortization of right-of-use assets us-gaap_FIFOInventoryAmount FIFO Inventory Amount Schedule of Inventory, Current [Table Text Block] us-gaap_InterestPayableCurrentAndNoncurrent Less interest Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block] Schedule of Cash and Cash Equivalents [Table Text Block] Accounts payable us-gaap_FinanceLeaseLiability Present value of minimum lease payments, finance us-gaap_PolicyTextBlockAbstract Accounting Policies senea_PolicyTable us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements us-gaap_TableTextBlock Notes Tables Thereafter us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive us-gaap_ComprehensiveIncomeNetOfTax Total Legal Matters and Contingencies [Text Block] Finance lease obligations Long-term lease obligations, finance us-gaap_FinanceLeaseLiabilityPaymentsDue Total minimum payment required, finance us-gaap_FinanceLeaseLiabilityCurrent Amount due within one year, finance Less interest, finance 2029, finance us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree Accrued payroll 2028, finance us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo Thereafter, finance us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive 2030, finance us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour Capital expenditures us-gaap_SegmentExpenditureAdditionToLongLivedAssets Subsequent Events [Text Block] Concentration Risk Type [Axis] Other State Tax Authorities [Member] Represents Other State Tax Authorities. 2027, finance Borrowings under revolving credit facility Illinois Tax Authority [Member] Represents the Illinois Tax Authority. Interest on lease obligations Operating cash flows from finance leases Accrued vacation Significant Accounting Policies [Text Block] Non-cash lease expense Less interest, operating Operating lease obligations Long-term lease obligations, operating Other accrued expenses us-gaap_OperatingLeaseLiability Present value of minimum lease payments, operating senea_ReceivablesPurchaseProgramPurchaseLimit Receivables Purchase Program, Purchase Limit Represents the purchase limit of receivables purchase program. us-gaap_OperatingLeaseLiabilityCurrent Amount due within one year, operating 2029 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive Thereafter 2030 Proceeds from the sale of assets 2027 Accounts Receivable [Member] 2028 Less current portion Amount due within one year Subtotal FIFO Basis [Member] Represents the FIFO basis. Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Concentration Risk Type [Domain] us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo 2028 us-gaap_LongTermDebtNoncurrent Long-term debt us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour 2030 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree 2029 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths 2027 2031 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive 2031 2032-2036 senea_FinanceLeaseCost Finance lease cost The total sum amount of amortization expense attributable to right-of-use asset from finance lease and the amount of interest expense on finance lease liability. us-gaap_ProceedsFromSaleAndCollectionOfReceivables Proceeds from Sale and Collection of Receivables Lessee, Lease Liability, Maturity [Table Text Block] Tabular disclosure of undiscounted cash flows of operating and finance lease liability. senea_PaymentsForAmountsIncludedInTheMeasurementOfLeaseLiabilitiesTotal Payments for Amounts Included in the Measurement of Lease Liabilities, Total The total amount for cash paid for amounts included in the measurement of lease liabilities. Standby Letters of Credit [Member] Carrying value us-gaap_LongTermDebt Total finance obligation Long-term debt Lessee, Operating and Finance Leases [Text Block] The entire disclosure for operating leases and finance leases of lessee. Includes, but is not limited to, description of operating and finance lease and maturity analysis of operating and finance lease liability. Rate of compensation increase us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease Statement of Stockholders' Equity [Abstract] Discount rate - benefit obligations us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate Loss Contingencies [Table] Expected return on plan assets us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-Term Rate of Return on Plan Assets Statement of Comprehensive Income [Abstract] Statement of Cash Flows [Abstract] us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent Change in pension and postretirement benefits, net of tax expense (benefit) of $7,050, $5,772 and ($1,628), respectively Percentage of Plan Assets us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion Convertible Preferred Stock, Shares Issued upon Conversion Stockholders' equity: Product Concentration Risk [Member] Long-Term Debt, Type [Domain] Equity Components [Axis] Borrowings under term loans, finance obligation and note payable Convertible Preferred Stock [Member] Equity Component [Domain] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] AOCI Attributable to Parent [Member] Fair Value, Inputs, Level 1 [Member] Equity [Text Block] Additional Paid-in Capital [Member] Retained Earnings [Member] Cost of products sold Cost of products sold Asset Acquisition [Table] Property, plant and equipment, net Property, plant and equipment, net Property, Plant and Equipment, Gross us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent Liability, Defined Benefit Plan Property, plant and equipment purchased on account Pension assets Subsequent Event Type [Domain] Subsequent Event [Table] Subsequent Event Type [Axis] Property, Plant, and Equipment [Policy Text Block] Schedule of Changes in Projected Benefit Obligations [Table Text Block] Machinery and Equipment [Member] Defined Benefit Plan, Assumptions [Table Text Block] Schedule of Allocation of Plan Assets [Table Text Block] Furniture and Fixtures [Member] Stock issued for profit sharing plan Schedule of Expected Benefit Payments [Table Text Block] us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefit Total Deferred income tax liability, net Deferred Income Tax Liabilities, Net Fair Value Disclosures [Text Block] Cumulative Preferred Stock [Member] Fair Value, by Balance Sheet Grouping [Table Text Block] us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefit Total Supplemental disclosures of cash flow information: Current liabilities: us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval us-gaap_LiabilitiesCurrent Total current liabilities us-gaap_CurrentFederalTaxExpenseBenefit Federal us-gaap_DebtInstrumentVariableInterestRateTypeExtensibleEnumeration Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] Supplier Concentration Risk [Member] Secured Overnight Financing Rate (SOFR) [Member] us-gaap_CurrentStateAndLocalTaxExpenseBenefit State us-gaap_AccountsReceivableNetCurrent Accounts receivable, net of allowance for credit losses of $53 and $71, respectively Current portion of long-term debt, finance and lease obligations Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue [Table Text Block] Fair value us-gaap_LongTermDebtFairValue Customer Concentration Risk [Member] us-gaap_TaxCreditCarryforwardAmount Tax Credit Carryforward, Amount us-gaap_PreferredStockLiquidationPreference Preferred Stock, Liquidation Preference Per Share Total long-term debt Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation. Defined Benefit Plan, Plan Assets, Category [Table Text Block] Lease, Cost [Table Text Block] us-gaap_TaxCreditCarryforwardValuationAllowance Tax Credit Carryforward, Valuation Allowance us-gaap_GainLossOnDispositionOfAssets1 (Gain) loss on the sale of assets Revenue Benchmark [Member] Long-Term Debt [Text Block] us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment Less: accumulated depreciation Accumulated other comprehensive loss Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block] General and administrative expense us-gaap_GeneralAndAdministrativeExpense Earnings before income taxes us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest Earnings before income taxes Additional paid-in capital LIFO (credit) charge Inventory, LIFO Reserve, Effect on Income, Net us-gaap_OtherOperatingIncomeExpenseNet Other operating (income) expense, net Use of Estimates, Policy [Policy Text Block] us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Additions to property, plant and equipment Payments to Acquire Property, Plant, and Equipment Equity incentive program UNITED STATES Outstanding principal Total minimum payments required Non-US [Member] Preferred stock conversion us-gaap_DebtInstrumentFaceAmount Debt Instrument, Face Amount Current assets: us-gaap_AssetsCurrent Total current assets Debt Instrument, Name [Domain] 401(k) match stock contribution us-gaap_DebtInstrumentMaturityDate Debt Instrument, Maturity Date us-gaap_DebtInstrumentInterestRateStatedPercentage Debt Instrument, Interest Rate, Stated Percentage Target Allocation Defined Benefit Plan, Plan Assets, Target Allocation, Percentage us-gaap_Depreciation Depreciation Class of Stock [Domain] Related and Nonrelated Parties [Axis] us-gaap_DebtInstrumentUnamortizedDiscount Debt Instrument, Unamortized Discount Receivables Purchase Agreement [Member] Represents the receivables purchase agreement. us-gaap_DebtInstrumentPeriodicPaymentPrincipal Debt Instrument, Periodic Payment, Principal us-gaap_TreasuryStockSharesAcquired Treasury Stock, Shares, Acquired Schedule of Long-Term Debt Instruments [Table] Debt Instrument [Axis] Additional shares to be issued under full conversion of preferred stock (in shares) us-gaap_TreasuryStockValue Treasury stock, at cost Treasury Stock, Value Cash flows from operating activities: us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash provided by operating activities Cash flows from financing activities: us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities us-gaap_PaymentsOfDebtIssuanceCosts Payments of debt issuance costs us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash (used in) provided by financing activities Advertising Cost [Policy Text Block] Fair Value Measured at Net Asset Value Per Share [Member] us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExcludingServiceCostStatementOfIncomeOrComprehensiveIncomeExtensibleList Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] us-gaap_AdvertisingExpense Advertising Expense Operating Segments [Member] us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan Stock Issued During Period, Shares, Employee Stock Ownership Plan Accounting Policies [Abstract] Long-Lived Asset, Excluding Intangible Asset and Goodwill, Impairment and Disposal [Policy Text Block] Segments [Domain] Accounts Receivable, Allowance for Credit Loss, Current Receivable [Policy Text Block] Segments [Axis] Diluted earnings per common share (in dollars per share) Corporate Segment and Other Operating Segment [Member] Basic earnings per common share (in dollars per share) us-gaap_IncomeLossFromContinuingOperations Net earnings Receivable with Imputed Interest [Table] Income Statement [Abstract] us-gaap_DeferredFederalIncomeTaxExpenseBenefit Federal Long Term Debt Excluding Finance Obligation [Member] Relating to long term debt excluding finance obligation. us-gaap_UnrecognizedTaxBenefits Beginning balance Ending balance Can Manufacturing Finance Obligation [Member] Relating to the Can Manufacturing Finance Obligation. us-gaap_DeferredIncomeTaxLiabilities Total liabilities us-gaap_NumberOfReportableSegments Number of Reportable Segments Deferred income taxes us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions Additions Treasury Stock, Common [Member] us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations Lapses in statues of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Net earnings Net earnings Net earnings Net earnings Right-of-use assets obtained in exchange for lease obligations Amount of right-of-use assets obtained from lease obligations. Right-of-use assets derecognized upon early lease termination Amount of right-of-use assets derecognized upon termination of the lease. senea_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingSettlementOrCurtailmentExpense Net periodic benefit cost Amount of expense (reversal of expense) for net periodic benefit cost components, excluding settlement or curtailment expense. Costs and expenses: Common Class A [Member] us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet Debt Issuance Costs, Line of Credit Arrangements, Net us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit State us-gaap_ConversionOfStockSharesConverted1 Conversion of Stock, Shares Converted (in shares) us-gaap_CostsAndExpenses Total costs and expenses us-gaap_DeferredTaxAssetsInventory Inventory valuation us-gaap_DeferredTaxAssetsGross Total assets Exchange of note payable for finance obligation and non-current deposits for property, plant and equipment Income Tax Disclosure [Text Block] Deferred revenue us-gaap_DeferredTaxAssetsDeferredIncome Net operating loss and other tax attribute carryovers Accounting Standards Update and Change in Accounting Principle [Table] us-gaap_DeferredTaxAssetsNet Total deferred income tax assets, net Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Axis] Income Tax, Policy [Policy Text Block] senea_DebtAgreementsFinancialCovenantsMinimumEBITDA Debt Agreements, Financial Covenants, Minimum EBITDA Represents the minimum EBITDA associated with financial covenants under debt agreements. us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate U.S. federal statutory rate, amount Future tax credits us-gaap_DeferredTaxAssetsOtherComprehensiveLoss Pension and post-retirement benefits us-gaap_DeferredTaxAssetsOther Other us-gaap_RelatedPartyTransactionAmountsOfTransaction Related Party Transaction, Amounts of Transaction Related and Nonrelated Parties [Domain] us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax Accumulated other comprehensive pre-tax loss us-gaap_DeferredFinanceCostsNet Unamortized debt issuance costs us-gaap_TreasuryStockValueAcquiredCostMethod Purchase treasury stock Treasury Stock, Value, Acquired, Cost Method Related Party Transaction [Table] us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax Net actuarial (gain) loss Insurance Related Party Transactions Disclosure [Text Block] Employee benefits us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes State income taxes (net of federal tax benefit)(1), amount us-gaap_IncomeTaxReconciliationTaxContingencies Changes in unrecognized tax benefits, amount us-gaap_IncomeTaxReconciliationOtherAdjustments Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Fair Value Hierarchy and NAV [Domain] us-gaap_IncomeTaxReconciliationTaxCredits Tax credits, amount Charged to other accounts Deductions from reserve Other income and expenses: us-gaap_RepaymentsOfLinesOfCredit Repayments of Lines of Credit us-gaap_ValuationAllowancesAndReservesBalance Balance Balance Statement of Financial Position [Abstract] us-gaap_RepaymentsOfLongTermLinesOfCredit Repayments under revolving credit facility us-gaap_DeferredTaxAssetsValuationAllowance Valuation allowance - noncurrent Charged (credited) to income SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities Deferred tax liabilities Cash paid for income taxes, net Income taxes paid, net of amounts refunded Inventory reserve SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Refundable income taxes SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] us-gaap_DeferredTaxLiabilities Deferred income tax liability, net Right-of-use assets us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets Intangibles Finance leases, lease term (Year) Vehicles [Member] us-gaap_DeferredTaxLiabilitiesOtherComprehensiveIncome Other comprehensive income us-gaap_RepaymentsOfUnsecuredDebt Payments on term loans and finance obligation Other assets us-gaap_PaymentsForRepurchaseOfCommonStock Purchase of treasury stock Document Information [Line Items] us-gaap_ConcentrationRiskPercentage1 Concentration Risk, Percentage Operating leases, lease term (Year) Document Information [Table] us-gaap_IncreaseDecreaseInOtherCurrentAssets Other assets us-gaap_DefinedBenefitPlanActuarialGainLoss Actuarial gain Service cost including administrative expenses Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan, including administration. us-gaap_BusinessAcquisitionsProFormaRevenue Pro forma net sales Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding Diluted (in shares) Total shares for diluted (in shares) Earnings per share: Receivables Purchase Program [Text Block] The disclosure for the receivables purchase program. 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Provision for restructuring and impairments Property, Plant, and Equipment [Text Block] Long-Lived Asset, Class [Domain] Legal Entity [Axis] Operating lease cost Short-term lease cost Construction in Progress [Member] us-gaap_LeaseCost Total lease cost Business Combination [Domain] Business Combination [Axis] Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table] Entity [Domain] us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax Total recognized in other comprehensive income Land and Land Improvements [Member] Business Combination, Pro Forma Information [Table Text Block] us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory Inventories Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Defined Benefit Plan, Debt Security [Member] Defined Benefit Plan, Cash [Member] us-gaap_PreferredStockDividendsPerShareDeclared Preferred Stock, Dividends Per Share, Declared (in dollars per share) us-gaap_PreferredStockDividendsPerShareCashPaid Preferred Stock, Dividends, Per Share, Cash Paid Software, In-Development, Internally Developed, and Purchased [Member] Building and Building Improvements [Member] us-gaap_OperatingIncomeLoss Operating income Fruit and Snack Segment [Member] Relating to the fruit and snack segment. us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet Assets acquired and liabilities assumed Vegetable Segment [Member] Relating to the vegetable segment. us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment Property, plant and equipment Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles Trade name LIFO Impact [Member] Relating to the impact of last in, first out inventory system. 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No Par Value Preferred Stock [Member] Represents the preferred stock without par value. senea_DeferredTaxLiabilitiesPension Pension Amount of deferred tax liability attributable to taxable temporary differences from pension. senea_DefinedContributionPlanEmployerDiscretionaryContributionValueOfShares Defined Contribution Plan, Employer Discretionary Contribution Value of Shares Amount of discretionary contributions made by an employer to a defined contribution plan in stock. us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted Earnings attributable to common stock on a diluted basis senea_DebtInstrumentCovenantMaximumPercentageOfCommitmentsForAvailableLineOfCreditThatRequiresMinimumFixedChargeCoverageRatio Debt Instrument, Covenant, Maximum Percentage of Commitments for Available Line of Credit that Requires Minimum Fixed Charge Coverage Ratio Represents the maximum percentage of commitments for available line of credit that requires minimum fixed charge coverage ratio. 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Total assets us-gaap_Assets Total assets Discount rate - service cost senea_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateServiceCost The interest rate used to adjust for the time value of money relating to service cost. 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Pension (benefit) cost us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount Defined Contribution Plan, Employer Discretionary Contribution Amount us-gaap_CommonStockCapitalSharesReservedForFutureIssuance Common Stock, Capital Shares Reserved for Future Issuance Percentage of revenue Represents the percentage of revenues. Diluted (in dollars per share) Canned Vegetables [Member] Represents information pertaining to canned vegetables. Revenue from Contract with Customer [Policy Text Block] us-gaap_ContractWithCustomerLiability Beginning balance Ending balance Green Giant [Member] Represents the Green Giant acquisition. Customer [Axis] Deferred revenue us-gaap_PaymentsToAcquireBusinessesGross Business acquisition Payments to Acquire Businesses, Gross Snack [Member] Represents the information pertaining to snack. Employee Benefit Plan, Real Estate [Member] Fruit [Member] Represents the information pertaining to fruit. Depreciation and amortization Depreciation and amortization Frozen [Member] Represents the information pertaining to the frozen products. Schedule of Cash Paid for Income Taxes [Table Text Block] Tabular disclosure of cash paid for income taxes. Schedule of Defined Benefit Plans Disclosures [Table Text Block] Non-taxable or non-deductible items, percent Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nontaxable or nondeductible items. senea_EffectiveIncomeTaxRateReconciliationNonTaxableOrNonDeductibleItemsAmount Non-taxable or non-deductible items, amount Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses or nontaxable items. Charitable Contributions [Member] Represents the information pertaining to charitable contributions. Related Party Foudation [Member] Represents a related party foundation, a nonprofit entity that supports charitable activities by making grants to unrelated organizations or institutions. Vegetables Supply [Member] Represents the information pertaining to vegetables supply. senea_PaymentsForNoncurrentDepositsInvestingActivities Increase in non-current deposits The cash outflow for non-current deposits classified as investing activities. senea_ReceivablesDerecognizedButContinuedToService Receivables Derecognized but Continued to Service Represents the amount of receivables derecognized but continued to service. 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Inventory Disclosure [Text Block] Fair Value, Inputs, Level 2 and Level 3 [Member] Fair value measurement inputs other than quoted prices included within level 1 that are observable for an asset or liability, either directly or indirectly, including, but not limited to, quoted prices for similar assets or liabilities in active markets, or quoted prices for identical or similar assets or liabilities in inactive markets (level 2) and unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. (level 3). Convertible from Series A Preferred Stock to Class A Stock [Member] Represents the conversion feature of Series A Preferred Stock that is convertible into Class A Stock. 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Stock, Class of Stock [Table] senea_ContractWithCustomerLiabilityAndRemainingPerformanceObligation Contract with Customer, Liability and Remaining Performance Obligation Represents the liability and remaining performance obligation of a contract with a customer. 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