Quarterly report pursuant to Section 13 or 15(d)

Description of Business, Basis of Presentation and Recent Accounting Pronouncements - Additional Information (Detail)

v3.21.1
Description of Business, Basis of Presentation and Recent Accounting Pronouncements - Additional Information (Detail)
3 Months Ended
Mar. 31, 2021
USD ($)
Office
Mar. 31, 2020
Office
Class of Stock [Line Items]    
Number of offices | Office 84  
Formation date 2013-06  
Percentage of common stock distributed 80.00%  
Commission's receivable settled period 10 days  
Line of credit | $ $ 0  
Credit Agreement [Member]    
Class of Stock [Line Items]    
Line of credit | $ $ 0  
Transaction Risk [Member]    
Class of Stock [Line Items]    
Concentration risk percentage 0.00% 0.00%
Customer Concentration Risk [Member] | Total revenues [Member]    
Class of Stock [Line Items]    
Concentration risk percentage 10.00% 10.00%
Customer Concentration Risk [Member] | Commissions receivable [Member]    
Class of Stock [Line Items]    
Concentration risk percentage 10.00% 10.00%
Geographic Concentration Risk [Member] | Total revenues [Member]    
Class of Stock [Line Items]    
Number of offices | Office 0 1
Concentration risk percentage 10.00% 10.00%
Geographic Concentration Risk [Member] | Total revenues [Member] | Maximum [Member] | CANADA [Member]    
Class of Stock [Line Items]    
Concentration risk percentage 2.00% 2.00%
IPO MMI [Member]    
Class of Stock [Line Items]    
IPO completion date Nov. 05, 2013