Note 1 - Principles of Consolidation and Basis of Presentation	9 Months Ended
Sep. 30, 2020
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1 – Principles of Consolidation and Basis of Presentation The interim consolidated financial statements included herein have been prepared by Rush Enterprises, Inc. and its subsidiaries (collectively referred to as the “Company”), without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). All adjustments have been made to the accompanying interim consolidated financial statements, which, in the opinion of the Company’s management, are necessary for a fair presentation of its operating results. All adjustments are of a normal recurring nature. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted pursuant to such rules and regulations. It is recommended that these interim consolidated financial statements be read in conjunction with the consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. Results of operations for interim periods are not necessarily indicative of results that may be expected for any other interim periods or the full fiscal year. Stock Split On September 15, 2020, the Board of Directors of the Company declared a 3-for-2 stock split of the Company’s Class A common stock and Class B common stock, to be effected in the form of a stock dividend. On October 12, 2020, the Company distributed one additional share of stock for every two shares of Class A common stock, par value $0.01 per share, and Class B common stock, par value $0.01 per share, held by shareholders of record as of September 28, 2020. All share and per share data in this Form 10-Q have been adjusted and restated to reflect the stock split as if it occurred on the first day of the earliest period presented. Adoption of New Accounting Pronouncements Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments - Credit Losses (“Topic 326”): Measurement of Credit Losses on Financial Instruments, was issued in June 2016. Under Topic 326, existing guidance on reporting credit losses for trade and other receivables, held-to-maturity debt securities and other instruments have been replaced with a new forward-looking "expected loss" model that results in the earlier recognition of allowances for losses. Under Topic 326, the Company is required to use a current expected credit loss (“CECL”) model that immediately recognizes an estimate of credit losses that are expected to occur over the life of the financial instruments that are within the scope of Topic 326. The CECL model uses a broader range of reasonable and supportable information in the development of credit loss estimates. The Company adopted Topic 326 on January 1, 2020, and the new standard did not result in a material impact on its consolidated financial statements. For a complete discussion of accounting for credit losses, see Note 12 – Accounts Receivable and Allowance for Credit Losses of the Notes to Consolidated Financial Statements. COVID-19 Risks and Uncertainties In March 2020, the World Health Organization made the assessment that COVID-19 could be characterized as a pandemic, and the President of the United States declared the COVID-19 outbreak a national emergency. The Company’s nationwide network of commercial vehicle dealerships are classified as “essential businesses” and have remained operational across the Company’s dealership network. Despite the dealerships remaining open, the COVID-19 pandemic had a significant negative impact on our financial results during the quarter ended September 30, 2020. The Company is unable to predict the impact that the COVID-19 pandemic will have on its future business and operating results due to numerous uncertainties, including the duration and severity of the outbreak.

Note 1 - Principles of Consolidation and Basis of Presentation

9 Months Ended

Sep. 30, 2020

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

1 – Principles of Consolidation and Basis of Presentation

The interim consolidated financial statements included herein have been prepared by Rush Enterprises, Inc. and its subsidiaries (collectively referred to as the “Company”), without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). All adjustments have been made to the accompanying interim consolidated financial statements, which, in the opinion of the Company’s management, are necessary for a fair presentation of its operating results. All adjustments are of a normal recurring nature. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted pursuant to such rules and regulations. It is recommended that these interim consolidated financial statements be read in conjunction with the consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. Results of operations for interim periods are not necessarily indicative of results that may be expected for any other interim periods or the full fiscal year.

Stock Split

On September 15, 2020, the Board of Directors of the Company declared a 3-for-2 stock split of the Company’s Class A common stock and Class B common stock, to be effected in the form of a stock dividend. On October 12, 2020, the Company distributed one additional share of stock for every two shares of Class A common stock, par value $0.01 per share, and Class B common stock, par value $0.01 per share, held by shareholders of record as of September 28, 2020. All share and per share data in this Form 10-Q have been adjusted and restated to reflect the stock split as if it occurred on the first day of the earliest period presented.

Adoption of New Accounting Pronouncements

Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments - Credit Losses (“Topic 326”): Measurement of Credit Losses on Financial Instruments, was issued in June 2016. Under Topic 326, existing guidance on reporting credit losses for trade and other receivables, held-to-maturity debt securities and other instruments have been replaced with a new forward-looking "expected loss" model that results in the earlier recognition of allowances for losses. Under Topic 326, the Company is required to use a current expected credit loss (“CECL”) model that immediately recognizes an estimate of credit losses that are expected to occur over the life of the financial instruments that are within the scope of Topic 326. The CECL model uses a broader range of reasonable and supportable information in the development of credit loss estimates. The Company adopted Topic 326 on January 1, 2020, and the new standard did not result in a material impact on its consolidated financial statements. For a complete discussion of accounting for credit losses, see Note 12 – Accounts Receivable and Allowance for Credit Losses of the Notes to Consolidated Financial Statements.

COVID-19 Risks and Uncertainties

In March 2020, the World Health Organization made the assessment that COVID-19 could be characterized as a pandemic, and the President of the United States declared the COVID-19 outbreak a national emergency. The Company’s nationwide network of commercial vehicle dealerships are classified as “essential businesses” and have remained operational across the Company’s dealership network. Despite the dealerships remaining open, the COVID-19 pandemic had a significant negative impact on our financial results during the quarter ended September 30, 2020. The Company is unable to predict the impact that the COVID-19 pandemic will have on its future business and operating results due to numerous uncertainties, including the duration and severity of the outbreak.