Fair value portion of the call option.

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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.

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Amount of expense for amortization of capitalized computer software costs.

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The carrying amount of capitalized computer software costs net of accumulated amortization as of the balance sheet date.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

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Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date for the rights acquired through a franchise arrangement having an indefinite period of benefit.

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Note 2 - Other Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Feb. 25, 2019
Capitalized Computer Software, Net, Ending Balance	$ 10,300
Capitalized Computer Software, Amortization	500	$ 11,100
Indefinite-Lived Franchise Rights	7,000		$ 7,000
Goodwill and Intangible Asset Impairment, Total	0
Rush Truck Centres of Canada Limited [Member]
Equity Method Investment, Ownership Percentage				50.00%
Rush Truck Centres of Canada Limited [Member] \| Other Assets [Member]
Equity Method Investments	19,400
Rush Truck Centres of Canada Limited [Member] \| Call Option [Member]
Equity Method Investment, Remaining Ownership Percentage Not Yet Acquired				50.00%
Rush Truck Centres of Canada Limited [Member] \| Call Option [Member] \| Other Assets [Member]
Call Option, Fair Value Disclosure	3,600
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,900
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,900
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,900
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,900
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 1,900
Components of ERP Platform Rquired Replacement [Member]
Capitalized Computer Software, Amortization			$ 19,900