Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Detail)

v3.8.0.1
Related-Party Transactions - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Related Party Transaction [Line Items]      
Aggregate principal amount for employee notes receivable $ 528,000   $ 621,000
MMC [Member]      
Related Party Transaction [Line Items]      
Real estate brokerage commissions and financing fees from transactions with subsidiaries of Marcus & Millichap Company 2,600,000 $ 203,000  
Commission expenses for transactions with subsidiaries of Marcus & Millichap Company 1,500,000 122,000  
Rent expense for lease $ 253,000 253,000  
Lease expiration date May 31, 2022    
Accounts payable and other accrued expenses - related party $ 101,000   $ 91,000
MMC [Member] | Transition Services Agreement [Member]      
Related Party Transaction [Line Items]      
Selling, general and administrative expense $ 72,000 $ 82,000  
Transition services agreement date Oct. 01, 2013    
George M. Marcus [Member]      
Related Party Transaction [Line Items]      
Beneficial ownership percentage 48.00%