Quarterly report pursuant to Section 13 or 15(d)

Equity - Additional Information (Detail)

v3.21.2
Equity - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
Sep. 30, 2021
Aug. 31, 2021
Jul. 31, 2021
Jun. 30, 2021
May 31, 2021
Mar. 31, 2021
Jan. 31, 2021
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Sep. 30, 2021
Sep. 30, 2020
Jul. 29, 2021
Class Of Stock [Line Items]                                
Partnership distributions, amount               $ 1,471,000     $ 1,497,000     $ 6,821,000 $ 6,521,000  
Distributions of partner incentive allocations of net income                           $ 27,819,000 27,236,000  
Treasury stock, aggregate price               $ 418,000                
Class B Common Stock                                
Class Of Stock [Line Items]                                
Share conversion, Shares               (11,000) (11,000) (8,000) (24,000) (12,000) (176,000)      
Issuance of common stock             34,196 44,000 2,000 56,000            
Class B Common Stock | Neosho                                
Class Of Stock [Line Items]                                
Issuance of common stock in connection with acquisition       1,740                        
Class B Common Stock | Cortina Asset Management, LLC                                
Class Of Stock [Line Items]                                
Issuance of common stock in connection with acquisition     44,267                          
Class B Common Stock | Restricted Stock                                
Class Of Stock [Line Items]                                
Issuance of common stock         20,876   21,598                  
Class B Common Stock | Resale And Registration Rights Agreement                                
Class Of Stock [Line Items]                                
Share conversion, Shares   10,651   5,864 4,743 7,605                    
Class B Common Stock | Silvercrest L.P                                
Class Of Stock [Line Items]                                
Issuance of common stock             34,196                  
Class A Common Stock                                
Class Of Stock [Line Items]                                
Share conversion, Shares               11,000 11,000 8,000 24,000 12,000 176,000      
Issuance of common stock         856                      
Treasury stock, purchased 27,197             27,000           27,197    
Treasury stock, aggregate price                           $ 418,000    
Class A Common Stock | Maximum                                
Class Of Stock [Line Items]                                
Stock repurchase program, authorized amount                               $ 15,000,000
Class A Common Stock | Restricted Stock                                
Class Of Stock [Line Items]                                
Issuance of common stock         856                      
Silvercrest L.P                                
Class Of Stock [Line Items]                                
Accrued partner incentive allocations               $ 9,196,000     $ 7,121,000     $ 26,210,000 $ 20,055,000