rr_RiskReturnAbstract rr_RiskReturnAbstract rr_ProspectusTable rr_ProspectusTable dei_DocumentInformationDocumentAxis dei_DocumentInformationDocumentAxis dei_DocumentDomain dei_DocumentDomain Legal Entity [Axis] Legal Entity [Axis] dei_EntityDomain dei_EntityDomain S000007577 [Member] Value Line U.S. Government Securities Fund S000007577 [Member] Prospectus Share Class [Axis] Prospectus Share Class [Axis] rr_ShareClassDomain rr_ShareClassDomain C000020642 [Member] Value Line U.S. Government Securities Fund C000020642 [Member] Performance Measure [Axis] Performance Measure [Axis] Performance Measure [Domain] Performance Measure [Domain] Barclays Capital Intermediate U.S. Government Bond Index [Member] Barclays Capital Intermediate U.S. Government Bond Index Barclays Capital Intermediate U.S. Government Bond Index [Member] Barclays Capital 50% Gov/50% MBS U.S. Government Bond Index [Member] Barclays Capital 50% Gov/50% MBS U.S. Government Bond Index Barclays Capital 50% Gov/50% MBS U.S. Government Bond Index [Member] Return after taxes on distributions Return after taxes on distributions Return after taxes on distributions Return after taxes on distributions and sale of Fund shares Return after taxes on distributions and sale of Fund shares Return after taxes on distributions and sale of Fund shares rr_ProspectusLineItems rr_ProspectusLineItems rr_RiskReturnHeading rr_RiskReturnHeading rr_ObjectiveHeading rr_ObjectiveHeading rr_ObjectivePrimaryTextBlock rr_ObjectivePrimaryTextBlock rr_ObjectiveSecondaryTextBlock rr_ObjectiveSecondaryTextBlock rr_ExpenseHeading rr_ExpenseHeading rr_ExpenseNarrativeTextBlock rr_ExpenseNarrativeTextBlock rr_ShareholderFeesCaption rr_ShareholderFeesCaption rr_ShareholderFeesTableTextBlock rr_ShareholderFeesTableTextBlock rr_OperatingExpensesCaption rr_OperatingExpensesCaption rr_AnnualFundOperatingExpensesTableTextBlock rr_AnnualFundOperatingExpensesTableTextBlock rr_ExpenseFootnotesTextBlock rr_ExpenseFootnotesTextBlock rr_ExpensesDeferredChargesTextBlock rr_ExpensesDeferredChargesTextBlock rr_ExpensesRangeOfExchangeFeesTextBlock rr_ExpensesRangeOfExchangeFeesTextBlock rr_ExpenseExampleHeading rr_ExpenseExampleHeading rr_ExpenseExampleByYearHeading rr_ExpenseExampleByYearHeading rr_ExpenseExampleNarrativeTextBlock rr_ExpenseExampleNarrativeTextBlock rr_ExpenseExampleByYearCaption rr_ExpenseExampleByYearCaption rr_ExpenseExampleWithRedemptionTableTextBlock rr_ExpenseExampleWithRedemptionTableTextBlock rr_ExpenseExampleNoRedemptionNarrativeTextBlock rr_ExpenseExampleNoRedemptionNarrativeTextBlock rr_ExpenseExampleNoRedemptionByYearCaption rr_ExpenseExampleNoRedemptionByYearCaption rr_ExpenseExampleNoRedemptionTableTextBlock rr_ExpenseExampleNoRedemptionTableTextBlock rr_ExpenseExampleFootnotesTextBlock rr_ExpenseExampleFootnotesTextBlock rr_ExpenseExampleClosingTextBlock rr_ExpenseExampleClosingTextBlock rr_PortfolioTurnoverHeading rr_PortfolioTurnoverHeading rr_PortfolioTurnoverTextBlock rr_PortfolioTurnoverTextBlock rr_StrategyHeading rr_StrategyHeading rr_StrategyNarrativeTextBlock rr_StrategyNarrativeTextBlock rr_RiskHeading rr_RiskHeading rr_RiskNarrativeTextBlock rr_RiskNarrativeTextBlock rr_RiskFootnotesTextBlock rr_RiskFootnotesTextBlock rr_RiskClosingTextBlock rr_RiskClosingTextBlock rr_BarChartAndPerformanceTableHeading rr_BarChartAndPerformanceTableHeading rr_PerformanceNarrativeTextBlock rr_PerformanceNarrativeTextBlock rr_BarChartNarrativeTextBlock rr_BarChartNarrativeTextBlock rr_BarChartHeading rr_BarChartHeading rr_BarChartTableTextBlock rr_BarChartTableTextBlock rr_BarChartFootnotesTextBlock rr_BarChartFootnotesTextBlock rr_BarChartClosingTextBlock rr_BarChartClosingTextBlock rr_PerformanceTableHeading rr_PerformanceTableHeading rr_PerformanceTableNarrativeTextBlock rr_PerformanceTableNarrativeTextBlock rr_PerformanceTableTextBlock rr_PerformanceTableTextBlock rr_MarketIndexPerformanceTableTextBlock rr_MarketIndexPerformanceTableTextBlock rr_PerformanceTableFootnotesTextBlock rr_PerformanceTableFootnotesTextBlock rr_PerformanceTableClosingTextBlock rr_PerformanceTableClosingTextBlock rr_OperatingExpensesAbstract rr_OperatingExpensesAbstract rr_OperatingExpensesColumnName rr_OperatingExpensesColumnName Management Fees Management Fees Distribution and Service (12b-1) Fees Distribution and Service (12b-1) Fees rr_DistributionOrSimilarNon12b1FeesOverAssets rr_DistributionOrSimilarNon12b1FeesOverAssets rr_Component1OtherExpensesOverAssets rr_Component1OtherExpensesOverAssets rr_Component2OtherExpensesOverAssets rr_Component2OtherExpensesOverAssets rr_Component3OtherExpensesOverAssets rr_Component3OtherExpensesOverAssets Other Expenses Other Expenses rr_AcquiredFundFeesAndExpensesOverAssets rr_AcquiredFundFeesAndExpensesOverAssets Total Annual Fund Operating Expenses Total Annual Fund Operating Expenses Less 12b-1 Fee Waiver* Less 12b-1 Fee Waiver Less 12b-1 Fee Waiver* Net Expenses Net Expenses rr_ExpenseExampleAbstract rr_ExpenseExampleAbstract rr_ExpenseExampleByYearColumnName rr_ExpenseExampleByYearColumnName Expense Example Year 01 1 year Expense Example Year 03 3 years Expense Example Year 05 5 years Expense Example Year 10 10 years rr_BarChartTableAbstract rr_BarChartTableAbstract rr_AnnualReturnCaption rr_AnnualReturnCaption rr_AnnualReturnColumnName rr_AnnualReturnColumnName rr_AnnualReturnInceptionDate rr_AnnualReturnInceptionDate rr_AnnualReturn1990 rr_AnnualReturn1990 rr_AnnualReturn1991 rr_AnnualReturn1991 rr_AnnualReturn1992 rr_AnnualReturn1992 rr_AnnualReturn1993 rr_AnnualReturn1993 rr_AnnualReturn1994 rr_AnnualReturn1994 rr_AnnualReturn1995 rr_AnnualReturn1995 rr_AnnualReturn1996 rr_AnnualReturn1996 rr_AnnualReturn1997 rr_AnnualReturn1997 rr_AnnualReturn1998 rr_AnnualReturn1998 rr_AnnualReturn1999 rr_AnnualReturn1999 rr_AnnualReturn2000 rr_AnnualReturn2000 2001 2001 2002 2002 2003 2003 2004 2004 2005 2005 2006 2006 2007 2007 2008 2008 2009 2009 2010 2010 Annual Return 2011 2011 2011 rr_AnnualReturn2012 rr_AnnualReturn2012 rr_AnnualReturn2013 rr_AnnualReturn2013 rr_AnnualReturn2014 rr_AnnualReturn2014 rr_AverageAnnualReturnAbstract rr_AverageAnnualReturnAbstract Average Annual Return Label Average Annual Return Label 1 year 1 year 5 years 5 years 10 years 10 years rr_AverageAnnualReturnSinceInception rr_AverageAnnualReturnSinceInception rr_AverageAnnualReturnInceptionDate rr_AverageAnnualReturnInceptionDate Document Type Document Type Document Period End Date Document Period End Date Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag dei_AmendmentDescription dei_AmendmentDescription Trading Symbol Trading Symbol Document Creation Date Document Creation Date Document Effective Date Document Effective Date rr_ProspectusDate rr_ProspectusDate rr_ShareholderFeesColumnName rr_ShareholderFeesColumnName rr_MaximumCumulativeSalesChargeOverOfferingPrice rr_MaximumCumulativeSalesChargeOverOfferingPrice rr_MaximumCumulativeSalesChargeOverOther rr_MaximumCumulativeSalesChargeOverOther rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice rr_MaximumDeferredSalesChargeOverOfferingPrice rr_MaximumDeferredSalesChargeOverOfferingPrice rr_MaximumDeferredSalesChargeOverOther rr_MaximumDeferredSalesChargeOverOther rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther rr_RedemptionFeeOverRedemption rr_RedemptionFeeOverRedemption rr_RedemptionFee rr_RedemptionFee rr_ExchangeFeeOverRedemption rr_ExchangeFeeOverRedemption rr_ExchangeFee rr_ExchangeFee rr_MaximumAccountFeeOverAssets rr_MaximumAccountFeeOverAssets rr_MaximumAccountFee rr_MaximumAccountFee rr_ShareholderFeeOther rr_ShareholderFeeOther rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination rr_PortfolioTurnoverRate rr_PortfolioTurnoverRate rr_ExpenseBreakpointDiscounts rr_ExpenseBreakpointDiscounts rr_ExpenseBreakpointMinimumInvestmentRequiredAmount rr_ExpenseBreakpointMinimumInvestmentRequiredAmount rr_ExpenseExchangeTradedFundCommissions rr_ExpenseExchangeTradedFundCommissions rr_ExpensesRepresentBothMasterAndFeeder rr_ExpensesRepresentBothMasterAndFeeder rr_ExpensesExplanationOfNonrecurringAccountFee rr_ExpensesExplanationOfNonrecurringAccountFee rr_OtherExpensesNewFundBasedOnEstimates rr_OtherExpensesNewFundBasedOnEstimates rr_AcquiredFundFeesAndExpensesBasedOnEstimates rr_AcquiredFundFeesAndExpensesBasedOnEstimates rr_ExpensesOtherExpensesHadExtraordinaryExpensesBeenIncluded rr_ExpensesOtherExpensesHadExtraordinaryExpensesBeenIncluded rr_ExpensesRestatedToReflectCurrent rr_ExpensesRestatedToReflectCurrent rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees rr_ExpenseExampleNoRedemptionYear01 rr_ExpenseExampleNoRedemptionYear01 rr_ExpenseExampleNoRedemptionYear03 rr_ExpenseExampleNoRedemptionYear03 rr_ExpenseExampleNoRedemptionYear05 rr_ExpenseExampleNoRedemptionYear05 rr_ExpenseExampleNoRedemptionYear10 rr_ExpenseExampleNoRedemptionYear10 rr_StrategyPortfolioConcentration rr_StrategyPortfolioConcentration rr_RiskLoseMoney rr_RiskLoseMoney rr_RiskNondiversifiedStatus rr_RiskNondiversifiedStatus rr_RiskMoneyMarketFund rr_RiskMoneyMarketFund rr_RiskNotInsuredDepositoryInstitution rr_RiskNotInsuredDepositoryInstitution rr_RiskCaption rr_RiskCaption rr_RiskColumnName rr_RiskColumnName rr_Risk rr_Risk rr_PerformanceInformationIllustratesVariabilityOfReturns rr_PerformanceInformationIllustratesVariabilityOfReturns rr_PerformanceOneYearOrLess rr_PerformanceOneYearOrLess rr_PerformanceAdditionalMarketIndex rr_PerformanceAdditionalMarketIndex rr_PerformanceAvailabilityPhone rr_PerformanceAvailabilityPhone rr_PerformanceAvailabilityWebSiteAddress rr_PerformanceAvailabilityWebSiteAddress rr_PerformancePastDoesNotIndicateFuture rr_PerformancePastDoesNotIndicateFuture rr_BarChartDoesNotReflectSalesLoads rr_BarChartDoesNotReflectSalesLoads rr_BarChartReasonSelectedClassDifferentFromImmediatelyPrecedingPeriod rr_BarChartReasonSelectedClassDifferentFromImmediatelyPrecedingPeriod rr_BarChartReturnsForClassNotOfferedInProspectus rr_BarChartReturnsForClassNotOfferedInProspectus rr_YearToDateReturnLabel rr_YearToDateReturnLabel rr_BarChartYearToDateReturnDate rr_BarChartYearToDateReturnDate rr_BarChartYearToDateReturn rr_BarChartYearToDateReturn rr_HighestQuarterlyReturnLabel rr_HighestQuarterlyReturnLabel rr_BarChartHighestQuarterlyReturnDate rr_BarChartHighestQuarterlyReturnDate rr_BarChartHighestQuarterlyReturn rr_BarChartHighestQuarterlyReturn rr_LowestQuarterlyReturnLabel rr_LowestQuarterlyReturnLabel rr_BarChartLowestQuarterlyReturnDate rr_BarChartLowestQuarterlyReturnDate rr_BarChartLowestQuarterlyReturn rr_BarChartLowestQuarterlyReturn rr_PerformanceTableDoesReflectSalesLoads rr_PerformanceTableDoesReflectSalesLoads rr_PerformanceTableMarketIndexChanged rr_PerformanceTableMarketIndexChanged rr_IndexNoDeductionForFeesExpensesTaxes rr_IndexNoDeductionForFeesExpensesTaxes rr_PerformanceTableUsesHighestFederalRate rr_PerformanceTableUsesHighestFederalRate rr_PerformanceTableNotRelevantToTaxDeferred rr_PerformanceTableNotRelevantToTaxDeferred rr_PerformanceTableOneClassOfAfterTaxShown rr_PerformanceTableOneClassOfAfterTaxShown rr_PerformanceTableExplanationAfterTaxHigher rr_PerformanceTableExplanationAfterTaxHigher rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod rr_PerformanceTableFootnotesReasonPerformanceInformationForClassDifferentFromImmediatelyPrecedingPeriod rr_AverageAnnualReturnCaption rr_AverageAnnualReturnCaption rr_AverageAnnualReturnColumnName rr_AverageAnnualReturnColumnName rr_MoneyMarketSevenDayYieldCaption rr_MoneyMarketSevenDayYieldCaption rr_MoneyMarketSevenDayYieldColumnName rr_MoneyMarketSevenDayYieldColumnName rr_MoneyMarketSevenDayYieldPhone rr_MoneyMarketSevenDayYieldPhone