Consolidated Balance Sheets June 30, 2012 (Unaudited) and December 31, 2011 Consolidated Balance Sheets June 30, 2012 (Unaudited) and December 31, 2011 [Abstract] Class of Stock [Domain] Assets Assets [Abstract] Current assets: Current assets: [Abstract] Cash and cash equivalents Accounts receivable, net Inventories, net Prepaid expenses and other Deferred income taxes, net Total current assets Investments Property and equipment, net Goodwill, net Other assets, net Total assets Liabilities and shareholders’ equity Liabilities and shareholders’ equity [Abstract] Current liabilities: Current liabilities: [Abstract] Amounts borrowed to finance the purchase of new and used commercial vehicle inventory. Floor plan notes payable Current maturities of long-term debt Current maturities of capital lease obligations Trade accounts payable Accrued expenses Total current liabilities Long-term debt, net of current maturities Capital lease obligations, net of current maturities Other long-term liabilities Deferred income taxes, net Shareholders’ equity: Shareholders’ equity: [Abstract] Preferred stock, par value $.01 per share; 1,000,000 shares authorized; 0 shares outstanding in 2012 and 2011 Common stock, par value $.01 per share; 60,000,000 class A shares and 20,000,000 class B shares authorized; 27,887,575 class A shares and 10,792,223 class B shares outstanding in 2012; and 27,406,424 class A shares and 10,776,697 class B shares outstanding in 2011 Additional paid-in capital Treasury stock, at cost: 1,639,843 class B shares Retained earnings Accumulated other comprehensive loss, net of tax Total shareholders’ equity Total liabilities and shareholders’ equity Preferred stock, par value (in Dollars per share) Preferred stock, shares authorized Preferred stock, shares outstanding Common stock, par value (in Dollars per share) Common stock, shares authorized Common stock, shares outstanding Treasury stock, shares Consolidated Statements of Income and Comprehensive Income (Unaudited) Consolidated Statements of Income and Comprehensive Income (Unaudited) [Abstract] Revenues: Revenues: [Abstract] New and used truck sales Aggregate revenue recognized during the period derived from parts sold to retail and wholesale customers, as well as revenue from commercial vehicle services and repairs. Parts and service Lease and rental Revenues recognized during the period representing fees earned for the arrangement of commercial vehicle financing for customers through various institutions as well as the sale of various insurance contracts to customers. Finance and insurance Other Total revenue Cost of products sold: Cost of products sold: [Abstract] New and used truck sales Total cost related to parts sold to retail and wholesale customers, as well as costs related to vehicle services and repairs. Parts and service Lease and rental Total cost of products sold Gross profit Selling, general and administrative Depreciation and amortization Gain on sale of assets Operating income Interest expense, net Income from before taxes Provision for income taxes Net income Earnings per common share: Earnings per common share: [Abstract] Basic (in Dollars per share) Diluted (in Dollars per share) Weighted average shares outstanding: Weighted average shares outstanding: [Abstract] Basic (in Shares) Diluted (in Shares) Comprehensive income Consolidated Statements of Cash Flows (Unaudited) Consolidated Statements of Cash Flows (Unaudited) [Abstract] Cash flows from operating activities: Cash flows from operating activities: [Abstract] Net income Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to reconcile net income to net cash provided by operating activities: [Abstract] Depreciation and amortization Gain on sale of property and equipment Stock-based compensation expense related to stock options and employee stock purchases Provision for deferred income tax expense Excess tax benefits from stock-based compensation Change in accounts receivable, net Change in inventories Change in prepaid expenses and other, net Change in trade accounts payable Change in accrued expenses The net change during the reporting period of floor plan notes payable with the manufacturer of new vehicles. Draws on floor plan notes payable – trade, net Net cash used in operating activities Cash flows from investing activities: Cash flows from investing activities: [Abstract] Acquisition of property and equipment Proceeds from the sale of property and equipment Business acquisitions Change in other assets Net cash used in investing activities Cash flows from financing activities: Cash flows from financing activities: [Abstract] Net change during the reporting period of floor plan notes payable to parties other than the manufacturer of new vehicles and all floor plan note payable related to used vehicles. Draws on floor plan notes payable – non-trade, net Proceeds from long-term debt Principal payments on long-term debt Principal payments on capital lease obligations Debt issuance costs Excess tax benefits from stock-based compensation Proceeds from issuance of shares relating to employee stock options and employee stock purchases Net cash provided by financing activities Net decrease in cash and cash equivalents Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Supplemental disclosure of cash flow information: Supplemental disclosure of cash flow information: [Abstract] Cash paid during the period for: Cash paid during the period for: [Abstract] Interest Income taxes, net of refunds Noncash investing activities: Noncash investing activities: [Abstract] Assets acquired under capital leases Note 1 - Principles of Consolidation and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Note 2 - Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Note 3 - Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Note 4 - Earnings Per Share Earnings Per Share [Text Block] Note 5 - Stock Options and Restricted Stock Awards Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Note 6 - Financial Instruments and Fair Value Fair Value Disclosures [Text Block] Note 7 - Segment Information Segment Reporting Disclosure [Text Block] Note 8 - Income Taxes Income Tax Disclosure [Text Block] Schedule of Goodwill [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of Derivative Instruments [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Goodwill Goodwill [Abstract] Significant Acquisitions and Disposals, Transaction [Domain] Balance January 1, 2012 Adjustment to goodwill Balance June 30, 2012 Basic and Diluted Earnings per Share Basic and Diluted Earnings per Share [Abstract] Numerator: Numerator: [Abstract] Numerator for basic and diluted earnings per share – Net income available to common shareholders (in Dollars) Denominator– Denominator– [Abstract] Denominator for basic earnings per share – weighted average shares outstanding Effect of dilutive securities– Effect of dilutive securities– [Abstract] Employee and director stock options and restricted share awards Denominator for diluted earnings per share – adjusted weighted average shares outstanding and assumed conversions Basic earnings per common share (in Dollars per share) Diluted earnings per common share and common share equivalents (in Dollars per share) Options to Purchase Common Stock Options to Purchase Common Stock [Abstract] Antidilutive Securities, Name [Domain] Anti-dilutive securities Investment in Auction Rate Securities Investment in Auction Rate Securities [Abstract] Cost Basis Amount Fair Value Derivative Financial Instruments Derivative Financial Instruments [Abstract] InterestRateSwapAgreement [Domain] Notional Amount Fixed Interest Rate Underlying Rate Expiration Date Fair Value Fair Values of Derivative Instruments Fair Values of Derivative Instruments [Abstract] Interest Rate Swaps Segment Reporting Information Segment Reporting Information [Abstract] Segment [Domain] Revenues from external customers Segment income (loss) from continuing operations before taxes Segment assets As of and for the six months ended June 30, 2012 As of and for the six months ended June 30, 2012 [Abstract] As of and for the three months ended June 30, 2011 As of and for the three months ended June 30, 2011 [Abstract] As of and for the six months ended June 30, 2011 As of and for the six months ended June 30, 2011 [Abstract] Indefinite-lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Other Assets, Noncurrent Finite-Lived Intangible Assets, Accumulated Amortization Depreciation, Depletion and Amortization Finite-Lived Intangible Asset, Useful Life Amortization of Intangible Assets Goodwill, Purchase Accounting Adjustments Share-based Compensation Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Available-for-sale Securities, Debt Securities, Noncurrent Available-for-sale Securities, Debt Maturities, Amortized Cost Basis Derivative, Basis Spread on Variable Rate Asset Impairment Charges Notional Amount of Interest Rate Cash Flow Hedge Derivatives Interest Rate Cash Flow Hedge Liability at Fair Value Number of Reportable Segments Number of Operating Segments Unrecognized Tax Benefits Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized Tax Benefits, Interest on Income Taxes Expense Business Segments [Axis] Scenario [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Computer Software, Intangible Asset [Member] Franchise Rights [Member] Indefinite-lived Intangible Assets by Major Class [Axis] Antidilutive Securities [Axis] Common Class A [Member] Scenario, Unspecified [Domain] All Other Segments [Member] Stock Options [Member] Common Class B [Member] Significant Acquisitions and Disposals by Transaction [Axis] Class of Stock [Axis] Interest Rate Swap Agreement [Axis] Interest Rate Swap Agreement [Axis] Interest Rate Swap Agreement 12 [Member] Interest Rate Swap Agreement 12 [Member] Interest Rate Swap Agreement 3 [Member] Interest Rate Swap Agreement 3 [Member] Interest Rate Swap Agreement 9 [Member] Interest Rate Swap Agreement 9 [Member] Interest Rate Swap Agreement 4 [Member] Interest Rate Swap Agreement 4 [Member] West Texas Peterbilt Acquisition [Member] West Texas Peterbilt Acquisition [Member] Interest Rate Swap Agreement 2 [Member] Interest Rate Swap Agreement 2 [Member] Interest Rate Swap Agreement 8 [Member] Interest Rate Swap Agreement 8 [Member] Truck Segment [Member] Truck Segment [Member] Interest Rate Swap Agreement 1 [Member] Interest Rate Swap Agreement 1 [Member] Interest Rate Swap Agreement 6 [Member] Interest Rate Swap Agreement 6 [Member] Interest Rate Swap Agreement 10 [Member] Interest Rate Swap Agreement 10 [Member] Acquisition Of Peck Road Ford [Member] Acquisition of Peck Road Ford [Member] Interest Rate Swap Agreement 11 [Member] Interest Rate Swap Agreement 11 [Member] Interest Rate Swap Agreement 5 [Member] Interest Rate Swap Agreement 5 [Member] Interest Rate Swap Agreement 7 [Member] Interest Rate Swap Agreement 7 [Member] Document and Entity Information [Abstract] CostOfProductsSoldPartsAndServiceSales Liabilities, Current Asset Impairment Charges Goodwill, Purchase Accounting Adjustments Amortization of Intangible Assets Interest Income (Expense), Net Net Cash Provided by (Used in) Investing Activities Document Period End Date Deferred Tax Liabilities, Net, Noncurrent Revenues Net Cash Provided by (Used in) Operating Activities Repayments of Long-term Capital Lease Obligations Cash and Cash Equivalents, Period Increase (Decrease) Assets, Current Amendment Flag Payments to Acquire Property, Plant, and Equipment Finite-Lived Intangible Assets, Accumulated Amortization Entity Central Index Key Cost of Goods Sold Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Unrecognized Tax Benefits Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities Net Cash Provided by (Used in) Financing Activities Entity Common Stock, Shares Outstanding Payments of Debt Issuance Costs Operating Leases, Rent Expense Cost of Revenue Repayments of Long-term Debt Number of Operating Segments Entity Filer Category Document Fiscal Year Focus Entity Public Float Payments for (Proceeds from) Other Investing Activities Entity Voluntary Filers Operating Income (Loss) Liabilities and Equity Available-for-sale Securities, Debt Maturities, Amortized Cost Basis Entity Current Reporting Status Entity Registrant Name Cash Flow Hedge Derivative Instrument Liabilities at Fair Value Unrecognized Tax Benefits that Would Impact Effective Tax Rate Finite-Lived Intangible Asset, Useful Life Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Derivative, Basis Spread on Variable Rate Entity Well-known Seasoned Issuer Stockholders' Equity Attributable to Parent Unrecognized Tax Benefits, Interest on Income Taxes Expense Amendment Description Document Type Number of Reportable Segments Treasury Stock, Value Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Depreciation, Depletion and Amortization Payments to Acquire Businesses, Gross Current Fiscal Year End Date Document Fiscal Period Focus Statement [Table] Statement [Line Items]