Document And Entity Information us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo Finite-Lived Intangible Assets, Amortization Expense, Year Two us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree Finite-Lived Intangible Assets, Amortization Expense, Year Three Note To Financial Statement Details Textual us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour Finite-Lived Intangible Assets, Amortization Expense, Year Four Note 4 - Earnings Per Share us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive Finite-Lived Intangible Assets, Amortization Expense, Year Five Note 6 - Financial Instruments and Fair Value us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo 2020 BMO Harris Bank N.A. [Member] Represents information pertaining to BMO Harris Bank N.A. Note 7 - Segment Information Note 9 - Revenue Note 10 - Leases us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Call Option [Member] Note 11 - Shareholders' Equity Note 13 - Accumulated Other Comprehensive Income Note 4 - Earnings Per Share - Earnings Per Share Calculation (Details) Note 4 - Earnings Per Share - Anti-dilutive Securities (Details) Income Tax Disclosure [Text Block] Note 6 - Financial Instruments and Fair Value - Pre-tax Effect of Interest Rate Swaps (Details) Note 7 - Segment Information - Segment Reporting Information (Details) Note 9 - Revenue - Disaggregated Revenue by Revenue Source (Details) Note 10 - Leases - Lease Cost (Details) Other assets, net Stock-based compensation expense related to employee stock options and employee stock purchases Note 10 - Leases - Maturities of Lease Liabilities (Details) us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear 2019 (a) us-gaap_LiabilitiesCurrent Total current liabilities Note 10 - Leases - Future Minimum Rental Receivable (Details) Note 10 - Leases - Rental Income (Details) us-gaap_GuaranteeObligationsMaximumExposure Guarantor Obligations, Maximum Exposure, Undiscounted Note 10 - Leases - Minimum Lease Payments Under Non-cancelable Leases (Details) Note 11 - Shareholders' Equity - Schedule of Shareholders' Equity (Details) Note 13 - Accumulated Other Comprehensive Income - Components of Accumulated Other Comprehensive Income (Details) Notes To Financial Statements Notes To Financial Statements [Abstract] Revenues from external customers us-gaap_Revenues Total revenue Parts and Service [Member] The performance of commercial vehicle repair services and the sale of commercial vehicle parts. New and Used Commercial Vehicle [Member] Represents the information pertaining to new and used commercial vehicle. rusha_CostOfRevenueLeaseAndRental Lease and rental The aggregate cost related to the lease and rental service. Long-lived assets held for sale, fair value Finance and Insurance [Member] Represents the information pertaining to finance and insurance. us-gaap_LesseeOperatingLeaseTermOfContract Lessee, Operating Lease, Term of Contract Components of ERP Platform Rquired Replacement [Member] Represents the components of ERP Platform that will require replacement. Floor plan notes payable Floor Plan Notes Payable Amounts borrowed to finance the purchase of new and used commercial vehicle inventory. us-gaap_GoodwillAndIntangibleAssetImpairment Goodwill and Intangible Asset Impairment, Total Commercial Vehicle Repair Service [Member] Represents the information pertaining to commercial vehicle repair service. Parts [Member] Represents the information pertaining to parts. Commercial Vehicle [Member] Represents the information pertaining to commercial vehicle. Depreciation and amortization us-gaap_DepreciationDepletionAndAmortization Draws on floor plan notes payable – trade, net rusha_IncreaseDecreaseInFloorPlanNotesPayableTradeNet Increase or decrease in amounts borrowed to finance the purchase of new and used commercial vehicle inventory. Guarantor Obligations, Nature [Axis] Draws (payments) on floor plan notes payable – non-trade, net The net change during the reporting period in commercial vehicle floor plan due by the reporting entity. Guarantor Obligations, Nature [Domain] Current maturities of long-term debt Financial Guarantee [Member] Insurance [Member] Represents the information pertaining to insurance service. us-gaap_AssetsCurrent Total current assets Stockholders' Equity Note Disclosure [Text Block] Line of credit Treasury stock (in shares) Assets held for sale Common stock, par value $.01 per share; 60,000,000 Class A shares and 20,000,000 Class B shares authorized; 28,186,893 Class A shares and 8,462,616 Class B shares outstanding in 2019; and 28,709,636 Class A shares and 8,290,277 Class B shares outstanding in 2018 Adjustments to reconcile net income to net cash provided by operating activities- Common stock, authorized (in shares) Customer deposits Common stock, par value (in dollars per share) Accrued expenses Acquisition of Country Ford Trucks [Member] Represents information pertaining to the acquisition of certain assets of Country Ford Trucks, which included real estate and a Ford truck franchise in Ceres, California, along with commercial vehicle and parts inventory. Statistical Measurement [Domain] us-gaap_OperatingLeasePayments Cash paid for amounts included in the measurement of lease liabilities Maximum [Member] us-gaap_ForeignCurrencyExchangeRateTranslation1 Foreign Currency Exchange Rate, Translation Minimum [Member] Revolving Credit Facility [Member] Schedule of Future Minimum Lease Payments for Capital Leases and Operating Leases [Table Text Block] Schedule of future minimum lease payments for capital leases and operating leases. Product and Service [Axis] Product and Service [Domain] Statistical Measurement [Axis] Investment, Name [Domain] Credit Facility [Axis] Proceeds from the sale of property and equipment Credit Facility [Domain] Preferred stock, par value $.01 per share; 1,000,000 shares authorized; 0 shares outstanding in 2019 and 2018 Interest us-gaap_PolicyTextBlockAbstract Accounting Policies Investment, Name [Axis] Preferred stock, authorized (in shares) Lease and rental Inventories, net Preferred stock, par value (in dollars per share) Right-of-use assets, net Amount of lessee's right to use underlying asset under leases. us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Acquisition of property and equipment Effect of dilutive securities– Employee and director stock options and restricted share awards (in shares) Weighted average shares outstanding: Income taxes paid, net Product and Service, Other [Member] Trade accounts payable Liabilities and shareholders’ equity Current liabilities: Truck Segment [Member] Represents the truck segment. Segment assets us-gaap_Assets Total assets Supplemental disclosure of cash flow information: Note receivable affiliate Other Assets Disclosure [Text Block] us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total Cash flows from operating activities: us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1 Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition us-gaap_SubleaseIncome Sublease Income Schedule of Segment Reporting Information, by Segment [Table Text Block] Statement [Line Items] us-gaap_NumberOfOperatingSegments Number of Operating Segments Accounts receivable, net us-gaap_NumberOfReportableSegments Number of Reportable Segments Computer Software, Intangible Asset [Member] Revenues: Finite-Lived Intangible Assets by Major Class [Axis] Share-based Payment Arrangement [Text Block] Finite-Lived Intangible Assets, Major Class Name [Domain] Rush Truck Centres of Canada Limited [Member] Information related to Rush Truck Centres of Canada Limited. AOCI Attributable to Parent [Member] Additional paid-in capital Shareholders’ equity: rusha_LesseeLeasesTermOfContract Lessee, Leases, Term of Contract Term of lessee's finance and operating leases, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. rusha_EquityMethodInvestmentRemainingOwnershipPercentageNotYetAcquired Equity Method Investment, Remaining Ownership Percentage Not Yet Acquired The remaining percentage of ownership not yet acquired of common stock or equity participation in the investee accounted for under the equity method of accounting. Segment Reporting Disclosure [Text Block] Award Type [Domain] Current assets: Numerator for basic and diluted earnings per share – Net income available to common shareholders Fair Value Disclosures [Text Block] Award Type [Axis] Net income Net income Assets Restricted Stock Units (RSUs) [Member] rusha_LesseeLeasesResidualValueGuaranteeAmount Lessee, Leases, Residual Value Guarantee, Amount The amount of residual value guarantee provided by lessee on leases. us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash provided by (used in) financing activities rusha_LessorLeasesTermOfContract Lessor, Leases, Term of Contract Term of lessor's leases, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Segment operating income us-gaap_OperatingIncomeLoss Operating income Share-based Payment Arrangement, Option [Member] us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash (used in) provided by operating activities Prepaid expenses and other us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Right-of-use assets obtained in exchange for lease obligations Amount of increase in right-of-use asset obtained in exchange for lease liability. Leases of Lessee and Lessor Disclosure [Text Block] The entire disclosure for lessee and lessor entity's leasing arrangements including, but not limited to, all of the following: (a.) The basis on which contingent rental payments are determined, (b.) The existence and terms of renewal or purchase options and escalation clauses, (c.) Restrictions imposed by lease agreements, such as those concerning dividends, additional debt, and further leasing. us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease Net decrease in cash and cash equivalents Total cost of products sold us-gaap_GrossProfit Gross profit Cost of products sold Lessee, Lease Liability, Maturity [Table Text Block] Tabular disclosure of lessee's lease liability. Weighted-average discount rate Weighted average discount rate for leases calculated at point in time. Weighted-average remaining lease term (months) (Month) Weighted average remaining lease term for leases, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Nonlease payments Amount of payments received by lessor for non lease. Minimum rental payments Amount of lease payments received by lessor for leases. us-gaap_IndefiniteLivedFranchiseRights Indefinite-Lived Franchise Rights Leases, Lease Income [Table Text Block] Tabular disclosure of components of income from leases. Commitments and Contingencies Disclosure [Text Block] Business Combination Disclosure [Text Block] Property and equipment, net Goodwill, net us-gaap_PaymentsOfDividends Payments of cash dividends us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter Thereafter, Capital Leases us-gaap_CapitalLeasesFutureMinimumPaymentsDue Total lease payments us-gaap_EquityMethodInvestmentOwnershipPercentage Equity Method Investment, Ownership Percentage us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears 2022, Capital Leases us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears 2023, Capital Leases us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears 2020, Capital Leases us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears 2021, Capital Leases Cost of products sold: Depreciation and Amortization [Member] The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. rusha_DebtInstrumentLoanLimitAmountForWorkingCapitalPurposes Debt Instrument, Loan Limit Amount for Working Capital Purposes The limit amount of the loan that can be used for working capital purposes. Other, net Vehicle Leases as Lessee 1 [Member] Represents the vehicle leases as lessee. rusha_DebtInstrumentLoanLimitAmountToPurchaseUsedInventory Debt Instrument, Loan Limit Amount to Purchase Used Inventory Amount of loan limit that can be used to purchase used inventory. us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent 2019, Capital Leases Cash flows from investing activities: us-gaap_PaymentsForRepurchaseOfCommonStock Common stock repurchased Earnings per common share: Retained Earnings [Member] Earnings Per Share [Text Block] Revenue us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments Less: Imputed interest Treasury Stock [Member] Equity in earnings of unconsolidated entities Issuance of shares relating to employee stock options and employee stock purchases us-gaap_EquityMethodInvestments Equity Method Investments Additional Paid-in Capital [Member] Common Stock [Member] us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments Income before taxes us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments Present value of lease liabilities Provision for income taxes Change in accrued expenses us-gaap_IncreaseDecreaseInAccruedLiabilities Equity Components [Axis] Equity Component [Domain] Other Assets [Member] Segment income (loss) before taxes us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest Change in trade accounts payable us-gaap_IncreaseDecreaseInAccountsPayableTrade Comprehensive Income (Loss) Note [Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Cash and cash equivalents Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period State and Local Jurisdiction [Member] Income Tax Authority [Axis] Income Tax Authority [Domain] Disaggregation of Revenue [Table Text Block] us-gaap_AllocatedShareBasedCompensationExpense Share-based Payment Arrangement, Expense Domestic Tax Authority [Member] us-gaap_RepaymentsOfLongTermDebt Principal payments on long-term debt rusha_LesseeOperatingLeaseOptionToTerminateTerm Lessee, Operating Lease, Option To Terminate Term Term of lessee's operating lease option to terminate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. us-gaap_RepaymentsOfLongTermCapitalLeaseObligations Principal payments on capital lease obligations Revenue from Contract with Customer [Text Block] rusha_CallOptionFairValueDisclosure Call Option, Fair Value Disclosure Fair value portion of the call option. Balance Sheet Location [Axis] Balance Sheet Location [Domain] Amendment Flag us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Accounting Policies [Abstract] us-gaap_OpenTaxYear Open Tax Year Comprehensive income Selling, General and Administrative Expenses [Member] Dividends declared per common share (in dollars per share) Common Stock, Dividends, Per Share, Declared us-gaap_GainLossOnSaleOfPropertyPlantEquipment (Gain) loss on sale of property and equipment, net Interest Expense [Member] Change in customer deposits us-gaap_IncreaseDecreaseInContractWithCustomerLiability us-gaap_SharesOutstanding Balance (in shares) Balance (in shares) Common stock, outstanding (in shares) Preferred stock, outstanding (in shares) us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued Unrecognized Tax Benefits, Income Tax Penalties Accrued us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued Unrecognized Tax Benefits, Interest on Income Taxes Accrued Current Fiscal Year End Date us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 Debt Instrument, Basis Spread on Variable Rate Proceeds from long-term debt us-gaap_DebtInstrumentInterestRateStatedPercentage Debt Instrument, Interest Rate, Stated Percentage Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets Change in prepaid expenses and other, net Document Fiscal Period Focus Operating lease cost Document Fiscal Year Focus Short-term lease cost Lease, Cost [Table Text Block] Document Period End Date Income Statement Location [Axis] Income Statement Location [Domain] Entity Emerging Growth Company Document Type Entity Small Business us-gaap_SalesTypeLeaseLeaseReceivable Sales-type Lease, Lease Receivable Document Information [Line Items] Document Information [Table] Entity Filer Category Debt Instrument [Axis] Entity Current Reporting Status Debt Instrument, Name [Domain] us-gaap_DividendsCommonStock Dividend Segments [Axis] London Interbank Offered Rate (LIBOR) [Member] Segments [Domain] Other Segments [Member] us-gaap_CapitalizedComputerSoftwareNet Capitalized Computer Software, Net, Ending Balance Variable Rate [Domain] us-gaap_LessorOperatingLeasePaymentsToBeReceived Total us-gaap_IncreaseDecreaseInReceivables Change in accounts receivable, net us-gaap_CapitalizedComputerSoftwareAmortization1 Capitalized Computer Software, Amortization Anti-dilutive options (in shares) Variable Rate [Axis] us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding Diluted (in shares) Denominator for diluted earnings per share – adjusted weighted average shares outstanding and assumed conversions (in shares) us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears 2023 us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter Thereafter us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear 2019 (a) Entity Central Index Key us-gaap_LeaseIncome Total Depreciation and amortization expense Entity Registrant Name us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears 2020 Proceeds from line of credit us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears 2021 Stock-based compensation related to stock options, restricted shares and employee stock purchase plan us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears 2022 Entity [Domain] Legal Entity [Axis] Statement [Table] Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Statement of Financial Position [Abstract] Diluted (in dollars per share) us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter Thereafter, Operating Leases Denominator for basic earnings per share – weighted average shares outstanding (in shares) us-gaap_WeightedAverageNumberOfSharesOutstandingBasic Basic (in shares) us-gaap_OperatingLeasesFutureMinimumPaymentsDue Total lease payments Diluted earnings per common share and common share equivalents (in dollars per share) Business Acquisition [Axis] us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears 2022, Operating Leases Basic (in dollars per share) Business Acquisition, Acquiree [Domain] us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears 2023, Operating Leases us-gaap_TreasuryStockValue Treasury stock, at cost: 4,430,753 Class A shares and 5,084,211 Class B shares in 2019 and 3,791,751 Class A shares and 5,030,787 Class B shares in 2018 Basic earnings per common share (in dollars per share) us-gaap_StockRepurchasedDuringPeriodShares Common stock repurchases (in shares) us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears 2020, Operating Leases Statement of Cash Flows [Abstract] us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears 2021, Operating Leases Entity Common Stock, Shares Outstanding (in shares) Foreign currency translation adjustment us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent 2019, Operating Leases Income Statement [Abstract] us-gaap_StockRepurchasedDuringPeriodValue Common stock repurchases us-gaap_IncreaseDecreaseInInventories Change in inventories Trading Symbol Finance lease cost – interest on lease liabilities Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Total lease payments Finance lease cost - amortization of right-of-use assets 2023 Issuance of common stock under employee stock purchase plan (in shares) 2024 and beyond us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount Less: Imputed interest Stock options exercised and stock awards (in shares) us-gaap_TableTextBlock Notes Tables 2020 2021 2022 Gain (loss) on sale of assets Issuance of common stock under employee stock purchase plan us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity Vesting of restricted share awards (in shares) Stock options exercised and stock awards Vesting of restricted share awards us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 2019 (a) Selling, general and administrative expense us-gaap_PaymentsForProceedsFromOtherInvestingActivities Other Cash flows from financing activities: Other long-term liabilities Line of Credit Facility, Lender [Domain] us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount Lender Name [Axis] us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and shareholders’ equity Deferred income taxes, net Retained earnings Accumulated other comprehensive income Interest expense, net us-gaap_StockholdersEquity Total shareholders’ equity Balance as of December 31, 2018 Balance at March 31, 2019 Common Class A [Member] us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements Common Class B [Member] us-gaap_PaymentsToAcquireEquityMethodInvestments Purchase of equity method investment and call option Subsequent Event [Member] Operating lease obligations, net of current maturities Class of Stock [Axis] Class of Stock [Domain] Long-term debt, net of current maturities Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] us-gaap_OperatingLeaseLiability Present value of lease liabilities us-gaap_PaymentsToAcquireBusinessesGross Payments to Acquire Businesses, Gross Business acquisitions Schedule of Stockholders Equity [Table Text Block] Option Indexed to Issuer's Equity, Type [Domain] Subsequent Event Type [Axis] Current maturities of operating lease obligations Subsequent Event Type [Domain] Current maturities of finance lease obligations Financial Service [Member] Finance lease obligations, net of current maturities Option Indexed to Issuer's Equity [Axis] Subsequent Events [Text Block] us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Total lease payments Floor Plan Credit Agreement [Member] Represents information regarding the Floor Plan Credit Agreement. us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount Less: Imputed interest Present value of lease liabilities Cash paid for amounts included in the measurement of lease liabilities Provision for deferred income tax expense us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree 2021 Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block] us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour 2022 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive 2023 us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive 2024 and beyond