Document And Entity Information us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo Finite-Lived Intangible Asset, Expected Amortization, Year Two us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree Finite-Lived Intangible Asset, Expected Amortization, Year Three Note To Financial Statement Details Textual us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour Finite-Lived Intangible Asset, Expected Amortization, Year Four Note 5 - Earnings Per Share us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive Finite-Lived Intangible Asset, Expected Amortization, Year Five Note 8 - Segment Information Note 10 - Revenue Note 11 - Leases Note 12 - Accumulated Other Comprehensive Income Call Option [Member] Note 13 - Accounts Receivable and Allowance for Credit Losses Other Receivables [Member] Related to other receivables. Note 5 - Earnings Per Share - Earnings Per Share Calculation (Details) Note 5 - Earnings Per Share - Anti-dilutive Securities (Details) Leasing, Parts and Service Receivables [Member] Related to leasing, parts and service receivables. Manufacturers' Receivables [Member] Related to manufacturers' receivables. Note 8 - Segment Information - Segment Reporting Information (Details) Income Tax Disclosure [Text Block] Note 10 - Revenue - Disaggregated Revenue by Revenue Source (Details) Commercial Vehicle Receivables [Member] Related to commercial vehicle receivables. Note 11 - Leases - Rental Income (Details) us-gaap_GuaranteeObligationsCurrentCarryingValue Guarantor Obligations, Current Carrying Value Note 12 - Accumulated Other Comprehensive Income - Components of Accumulated Other Comprehensive Income (Details) Note 13 - Accounts Receivable and Allowance for Credit Losses - Allowance for Accounts Receivable (Details) Stock-based compensation expense related to employee stock options and employee stock purchases Other assets, net us-gaap_LiabilitiesCurrent Total current liabilities Notes To Financial Statements Notes To Financial Statements [Abstract] us-gaap_GuaranteeObligationsMaximumExposure Guarantor Obligations, Maximum Exposure, Undiscounted 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. Finance and Insurance [Member] Represents the information pertaining to finance and insurance. us-gaap_LesseeOperatingLeaseTermOfContract Lessee, Operating Lease, Term of Contract (Year) 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 (Payments) 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] (Payments) draws 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] Financial Guarantee [Member] Insurance [Member] Represents the information pertaining to insurance service. us-gaap_SharesIssued Balance (in shares) Balance (in shares) Other comprehensive income us-gaap_AssetsCurrent Total current assets 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; 27,532,890 Class A shares and 8,410,440 Class B shares outstanding in 2020; and 27,953,648 Class A shares and 8,240,486 Class B shares outstanding in 2019 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 Statistical Measurement [Domain] Maximum [Member] us-gaap_ForeignCurrencyExchangeRateTranslation1 Foreign Currency Exchange Rate, Translation Minimum [Member] Product and Service [Axis] Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Product and Service [Domain] Statistical Measurement [Axis] Investment, Name [Domain] Proceeds from the sale of property and equipment Preferred stock, par value $.01 per share; 1,000,000 shares authorized; 0 shares outstanding in 2020 and 2019 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) us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Acquisition of property and equipment Employee and director stock options and restricted share awards (in shares) Noncash investing and financing activities: Assets acquired under finance leases Weighted average shares outstanding: Income taxes paid (refunded), net Product and Service, Other [Member] Trade accounts payable Goodwill Disclosure [Text Block] Current liabilities: Truck Segment [Member] Represents the truck segment. Supplemental disclosure of cash flow information: Segment assets us-gaap_Assets Total assets 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 (Year) Schedule of Segment Reporting Information, by Segment [Table Text Block] Statement [Line Items] Allowances for credit losses Balance Balance us-gaap_NumberOfOperatingSegments Number of Operating Segments Accounts receivable (less allowances for credit losses of $1,679 and $1,424, respectively) 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: Other income 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: Net income available to common shareholders Fair Value Disclosures [Text Block] Award Type [Axis] Net income Net income Restricted Stock Units (RSUs) [Member] us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash provided by (used in) financing activities Segment operating income (loss) us-gaap_OperatingIncomeLoss Operating income Share-based Payment Arrangement, Option [Member] us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash (used in) provided by operating activities us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities Prepaid expenses and other Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] 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 us-gaap_CostOfGoodsAndServicesSold Cost of products sold Nonlease payments Amount of payments received by lessor for non lease. Deferred income taxes, net 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] Property and equipment, net Goodwill, net us-gaap_PaymentsOfDividends Payments of cash dividends us-gaap_EquityMethodInvestmentOwnershipPercentage Equity Method Investment, Ownership Percentage Cost of products sold Other, net Cash flows from investing activities: us-gaap_PaymentsForRepurchaseOfCommonStock Common stock repurchased Earnings per common share: Retained Earnings [Member] Earnings Per Share [Text Block] Revenue Treasury Stock [Member] Equity in earnings of unconsolidated entities Proceeds from 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] Income tax provision Change in accrued expenses us-gaap_IncreaseDecreaseInAccruedLiabilities Equity Components [Axis] Equity Component [Domain] Other Noncurrent Liabilities [Member] Other Assets [Member] Segment income (loss) before taxes us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest Income before taxes 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] 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] Document Quarterly Report Amendment Flag Entity Incorporation, State or Country Code us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Accounting Policies [Abstract] us-gaap_OpenTaxYear Open Tax Year Comprehensive income Document Transition Report City Area Code Selling, General and Administrative Expenses [Member] Entity Interactive Data Current us-gaap_RepaymentsOfMediumTermNotes Principal payments on long-term debt Dividends declared per common share (in dollars per share) us-gaap_GainLossOnSaleOfPropertyPlantEquipment Gain on sale of property and equipment, net Change in customer deposits us-gaap_IncreaseDecreaseInContractWithCustomerLiability Security Exchange Name Common stock, outstanding (in shares) Financing Receivable, Allowance for Credit Loss [Table Text Block] Preferred stock, outstanding (in shares) Title of 12(b) Security us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs Write offs against allowance, net of recoveries Write offs against allowance, net of recoveries 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 Proceeds from long-term debt Receivable Type [Axis] Receivable [Domain] us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets Change in prepaid expenses and other, net Document Fiscal Period Focus Document Fiscal Year Focus Document Period End Date Income Statement Location [Axis] Income Statement Location [Domain] Entity File Number Entity Emerging Growth Company Document Type Entity Small Business Entity Shell Company us-gaap_SalesTypeLeaseLeaseReceivable Sales-type Lease, Lease Receivable Document Information [Line Items] Document Information [Table] Entity Filer Category Entity Current Reporting Status us-gaap_DividendsCommonStock Dividends Segments [Axis] Segments [Domain] Other Segments [Member] us-gaap_CapitalizedComputerSoftwareNet Capitalized Computer Software, Net, Ending Balance us-gaap_IncreaseDecreaseInReceivables Change in accounts receivable, net us-gaap_CapitalizedComputerSoftwareAmortization1 Capitalized Computer Software, Amortization us-gaap_GoodwillImpairmentLoss Goodwill, Impairment Loss Weighted average anti-dilutive options (in shares) Diluted (in shares) Denominator for diluted earnings per share – adjusted weighted average shares outstanding and assumed conversions (in shares) Current maturities of long-term debt Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations and line of credit. Entity Tax Identification Number Entity Central Index Key us-gaap_LeaseIncome Total Depreciation and amortization expense Entity Registrant Name Proceeds from line of credit Stock-based compensation related to stock options, restricted shares and employee stock purchase plan Entity [Domain] Legal Entity [Axis] Statement [Table] Entity Address, Address Line One Statement of Financial Position [Abstract] us-gaap_EarningsPerShareDiluted Diluted (in dollars per share) Denominator for basic earnings per share – weighted average shares outstanding (in shares) Basic (in shares) us-gaap_TreasuryStockValueAcquiredCostMethod Common stock repurchases Entity Address, City or Town Diluted earnings per common share and common share equivalents (in dollars per share) Entity Address, Postal Zip Code us-gaap_EarningsPerShareBasic Basic (in dollars per share) Entity Address, State or Province us-gaap_TreasuryStockValue Treasury stock, at cost: 5,610,906 Class A shares and 5,360,832 Class B shares in 2020 and 5,055,783 Class A shares and 5,306,341 Class B shares in 2019 Basic earnings per common share (in dollars per share) Statement of Cash Flows [Abstract] Entity Common Stock, Shares Outstanding Statement of Stockholders' Equity [Abstract] us-gaap_StockRepurchasedAndRetiredDuringPeriodShares Common stock repurchases (in shares) Foreign currency translation adjustment Income Statement [Abstract] us-gaap_IncreaseDecreaseInInventories Change in inventories Trading Symbol Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Issuance of common stock under employee stock purchase plan (in shares) Local Phone Number Stock options exercised and stock awards (in shares) us-gaap_TableTextBlock Notes Tables Gain on sale of assets Issuance of common stock under employee stock purchase plan Vesting of restricted share awards (in shares) Stock options exercised and stock awards Vesting of restricted share awards Selling, general and administrative expense Current period provision us-gaap_PaymentsForProceedsFromOtherInvestingActivities Other Cash flows from financing activities: Other long-term liabilities us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and shareholders’ equity Retained earnings Accumulated other comprehensive income Interest expense, net us-gaap_StockholdersEquity Total shareholders’ equity Balance Balance 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 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_PaymentsToAcquireBusinessesGross Business acquisitions Option Indexed to Issuer's Equity, Type [Domain] Current maturities of operating lease obligations Current maturities of finance lease obligations Financial Service [Member] Finance lease obligations, net of current maturities Option Indexed to Issuer's Equity [Axis] Operating lease right-of-use assets, net us-gaap_FinanceLeasePrincipalPayments Principal payments on finance lease obligations Provision for deferred income tax expense us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year