Quarterly report pursuant to Section 13 or 15(d)

Cover Page

v3.21.1
Cover Page - shares
3 Months Ended
Mar. 31, 2021
May 04, 2021
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Mar. 31, 2021  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Registrant Name MARCUS & MILLICHAP, INC.  
Entity Interactive Data Current Yes  
Title of 12(b) Security Common Stock  
Trading Symbol MMI  
Security Exchange Name NYSE  
Entity File Number 001-36155  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 35-2478370  
Entity Address, Address Line One 23975 Park Sorrento, Suite 400  
Entity Address, City or Town Calabasas  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 91302  
City Area Code 818  
Local Phone Number 212-2250  
Entity Shell Company false  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   39,530,910
Amendment Flag false  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Entity Central Index Key 0001578732  
Current Fiscal Year End Date --12-31