v3.5.0.2
Document And Entity Information - shares
6 Months Ended
Jun. 30, 2016
Aug. 01, 2016
Common Class B [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   9,966,230
Common Class A [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   29,695,203
Entity Registrant Name RUSH ENTERPRISES INC \TX\  
Entity Central Index Key 0001012019  
Trading Symbol rusha  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Well-known Seasoned Issuer Yes  
Document Type 10-Q  
Document Period End Date Jun. 30, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q2  
Amendment Flag false