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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No definition available.

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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 for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in remainder of current fiscal year.

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No definition available.

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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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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No definition available.

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The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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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) $ in Thousands, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Apr. 25, 2019 CAD ($)	Feb. 25, 2019
Indefinite-Lived Franchise Rights	$ 7,000		$ 7,000
Goodwill and Intangible Asset Impairment, Total	0		0
Capitalized Computer Software, Net, Ending Balance	6,500
Capitalized Computer Software, Amortization	500	$ 500
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year	1,500
Finite-Lived Intangible Asset, Expected Amortization, Year One	1,200
Finite-Lived Intangible Asset, Expected Amortization, Year Two	1,200
Finite-Lived Intangible Asset, Expected Amortization, Year Three	1,200
Finite-Lived Intangible Asset, Expected Amortization, Year Four	1,200
Financial Guarantee [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted				$ 250
Other Noncurrent Liabilities [Member] \| Financial Guarantee [Member]
Guarantor Obligations, Current Carrying Value	5,300		$ 5,200
Rush Truck Centres of Canada Limited [Member]
Equity Method Investment, Ownership Percentage					50.00%
Rush Truck Centres of Canada Limited [Member] \| Other Noncurrent Liabilities [Member]
Equity Method Investments	33,200
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