Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Detail)

v3.10.0.1
Related-Party Transactions - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Related Party Transaction [Line Items]          
Aggregate principal amount for employee notes receivable $ 323,000   $ 323,000   $ 621,000
MMC [Member]          
Related Party Transaction [Line Items]          
Real estate brokerage commissions and financing fees from transactions with subsidiaries of Marcus & Millichap Company 1,800,000 $ 309,000 4,900,000 $ 632,000  
Commission expenses for transactions with subsidiaries of Marcus & Millichap Company 1,100,000 181,000 2,900,000 368,000  
Rent expense for lease 257,000 253,000 $ 765,000 759,000  
Lease expiration date     May 31, 2022    
Accounts payable and other liabilities - related party 91,000   $ 91,000   $ 91,000
MMC [Member] | Transition Services Agreement [Member]          
Related Party Transaction [Line Items]          
Selling, general and administrative expense $ 20,000 $ 43,000 $ 147,000 $ 168,000  
Transition services agreement date     Oct. 01, 2013    
George M. Marcus [Member]          
Related Party Transaction [Line Items]          
Beneficial ownership percentage     42.00%