Document and Entity Information
9 Months Ended
Sep. 30, 2015
Oct. 28, 2015
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2015  
Document Fiscal Year Focus 2015  
Document Fiscal Period Focus Q3  
Trading Symbol MGRC  
Entity Registrant Name MCGRATH RENTCORP  
Entity Central Index Key 0000752714  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   23,885,220