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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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For each balance sheet presented, the amount of accumulated amortization for 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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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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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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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Represents the number of stores.

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Note 2 - Other Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended
	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 SAP Enterprise Software And SAP Dealership Management System [Member] Sales Revenue, Net [Member]	Sep. 30, 2014 Rush Truck Centers [Member]	Sep. 30, 2014 Computer Software, Intangible Asset [Member]	Sep. 30, 2013 Computer Software, Intangible Asset [Member]	Sep. 30, 2014 Computer Software, Intangible Asset [Member]	Sep. 30, 2013 Computer Software, Intangible Asset [Member]
Note 2 - Other Assets (Details) [Line Items]
Capitalized Computer Software, Net		$ 39.1
Capitalized Computer Software, Accumulated Amortization		9.5
Finite-Lived Intangible Asset, Useful Life								15 years
Number of Stores					83
Concentration Risk, Percentage				70.00%
Amortization of Intangible Assets						0.8	0.7	2.4	2.2
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months			3.3
Finite-Lived Intangible Assets, Amortization Expense, Year Two			3.3
Finite-Lived Intangible Assets, Amortization Expense, Year Three			3.3
Finite-Lived Intangible Assets, Amortization Expense, Year Five			3.3
Finite-Lived Intangible Assets, Amortization Expense, Year Four		3.3
Indefinite-Lived Franchise Rights	4.5	4.5
Goodwill and Intangible Asset Impairment	$ 0