Note 11 - Share Based Compensation And Employee Benefit Plans (Detail) (USD $)	12 Months Ended										12 Months Ended		12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2012 Common Class A [Member] The 2007 Long-Term Incentive Plan [Member]	May 18, 2010 Common Class A [Member] The 2007 Long-Term Incentive Plan [Member]	Dec. 31, 2012 Common Class B [Member] The 2007 Long-Term Incentive Plan [Member]	May 18, 2010 Common Class B [Member] The 2007 Long-Term Incentive Plan [Member]	Dec. 31, 2012 Highly Compensated Employees [Member]	Dec. 31, 2012 Employee Stock Purchase Plan [Member]	Dec. 31, 2012 The 2006 Non-Employee Director Stock Option Plan [Member]	Dec. 31, 2011 The 2006 Non-Employee Director Stock Option Plan [Member]	May 18, 2010 The 2006 Non-Employee Director Stock Option Plan [Member]	May 16, 2006 The 2006 Non-Employee Director Stock Option Plan [Member]	Dec. 31, 2012 The 2007 Long-Term Incentive Plan [Member]	Dec. 31, 2011 The 2007 Long-Term Incentive Plan [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2011 Shares Issued to Three Non-Employee Directors [Member]	Dec. 31, 2011 Shares Issued to One Non-Employee Director [Member]	Dec. 31, 2012 Shares Issued to Two Non-Employee Directors [Member]
Maximum Percentage of Salary for Employee Stock Purchase	10.00%
Purchase Price Description, Employee Stock Purchase Plan	The employee's purchase price is 85% of the lesser of the closing price of the Class A common stock on the first business day or the last business day of the semi-annual offering period, as reported by The NASDAQ Global Select Market SM
Maximum Fair Value for Employee Stock Purchase Per Year	$ 25,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in Shares)							1,129,000		450,000			394,000	256,000
Common Stock, Capital Shares Reserved for Future Issuance (in Shares)												900,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in Shares)	70,998	62,405
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)								4,550,000		450,000			500,000			1,500,000
Reduction in Number of Shares Reserved for Issuance (in Shares)															1,000,000
Number of Shares Available for Purchase with Options by Non-Employee Director Each Year (in Shares)	20,000
Stock Option Term	10 years																10 years
Share-based Goods and Nonemployee Services Transaction, Expense	125,000	125,000		100,000	125,000
Share-based Goods and Nonemployee Services Transaction, Quantity of Securities Issued (in Shares)																					6,309	3,785	7,901
Payment to Non-Employee Directors		50,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in Shares)													31,604	22,712
Share-based Compensation Arrangement by Share-based Payment Award, Description																	The aggregate number of shares of common stock subject to stock options or SARs that may be granted to any one participant in any year under the 2007 Incentive Plan is 100,000shares of Class A common stock or 100,000 shares of Class B common stock.
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)	636,320																636,320	647,145
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in Shares)						161,239											129,635	103,985
Share-based Compensation	7,332,000	5,683,000	4,468,000
Proceeds from Stock Options Exercised	5,100,000	5,500,000	2,300,000
Share Price (in Dollars per share)	$ 20.67
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	5,600,000	5,200,000	2,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	2,400,000	2,500,000	2,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$ 10.95	$ 8.68	$ 5.80
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	three
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value						1,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$ 21.98	$ 18.93	$ 13.08			$ 21.98
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	10,400,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	2 years
Description of Defined Contribution Pension and Other Postretirement Plans	Each employee who has completed 90 days of continuous service is entitled to enter the Rush 401k Plan on the first day of the following month
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent											15.00%								1.00%	50.00%
Defined Contribution Plan, Employer Matching Contributions Descriptions	For the first 10% of an employee's contribution, the Company contributed an amount equal to 5% of the employees' contributions for those employees with less than five years of service and an amount equal to 10% of the employees' contributions for those employees with more than five years of service.Effective January 1, 2011, for the first 10% of an employee's contribution, the Company contributed an amount equal to 15% of the employees' contributions for those employees with less than five years of service and an amount equal to 30% of the employees' contributions for those employees with more than five years of service.Effective February 1, 2012, for the first 10% of an employee's contribution, the Company contributed an amount equal to 20% of the employees' contributions for those employees with less than five years of service and an amount equal to 40% of the employees' contributions for those employees with more than five years of service.
Defined Contribution Plan, Cost Recognized	3,700,000	2,200,000	400,000
Deferred Compensation Arrangement with Individual, Description	100%
Deferred Compensation Liability, Current	$ 600,000	$ 100,000