Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Jul. 29, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
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 Current Reporting Status Yes  
Entity Shell Company false  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity File Number 0-13292  
Entity Tax Identification Number 942579843  
Entity Address, Address Line One 5700 Las Positas Road  
Entity Address, City or Town Livermore  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 94551-7800  
City Area Code 925  
Local Phone Number 606-9200  
Entity Common Stock, Shares Outstanding   24,253,091