Annual report pursuant to Section 13 and 15(d)

Equity - Additional Information (Detail)

v3.20.4
Equity - Additional Information (Detail) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Dec. 31, 2020
Nov. 30, 2020
Aug. 31, 2020
Jun. 30, 2020
May 31, 2020
Mar. 31, 2020
Feb. 29, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Class Of Stock [Line Items]                    
Partnership distributions, amount               $ 6,297 $ 7,698 $ 6,773
Distributions of partner incentive allocations of net income               $ 27,328 $ 27,199 $ 24,935
Share conversion, Shares     24,191              
Class B Common Stock                    
Class Of Stock [Line Items]                    
Share conversion, Shares 69,724 36,361     7,355     (318,000) (810,000) (374,000)
Issuance of common stock         9,546       665,000 6,000
Class B Common Stock | Resale And Registration Rights Agreement                    
Class Of Stock [Line Items]                    
Share conversion, Shares 69,724 36,361 24,191 5,400 7,355 20,662 155,224      
Class A Common Stock                    
Class Of Stock [Line Items]                    
Share conversion, Shares               318,000 810,000 374,000
Issuance of common stock         1,896          
Silvercrest L.P                    
Class Of Stock [Line Items]                    
Accrued partner incentive allocations               $ 27,467 $ 27,229 $ 27,197