Annual report pursuant to Section 13 and 15(d)

Equity - Additional Information (Detail)

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Equity - Additional Information (Detail) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Dec. 31, 2019
Nov. 30, 2019
Aug. 31, 2019
Jul. 31, 2019
Jun. 30, 2019
May 31, 2019
Mar. 31, 2019
Jan. 31, 2019
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Class Of Stock [Line Items]                      
Partnership distributions, amount                 $ 7,698 $ 6,773 $ 6,205
Distributions of partner incentive allocations of net income                 $ 27,199 $ 24,935 $ 21,177
Class B Common Stock                      
Class Of Stock [Line Items]                      
Share conversion, Shares 133,812 16,054             (810,000) (374,000) (63,000)
Issuance of common stock     241,624     948     665,000 6,000 13,000
Class B Common Stock | Resale And Registration Rights Agreement                      
Class Of Stock [Line Items]                      
Share conversion, Shares 133,812 16,054 556,293   2,386 84,268 17,074        
Class B Common Stock | Neosho                      
Class Of Stock [Line Items]                      
Issuance of Class B common stock in connection with the Acquisition               1,516      
Class B Common Stock | Cortina                      
Class Of Stock [Line Items]                      
Issuance of Class B common stock in connection with the Acquisition       662,713              
Class B Common Stock | Cortina | Resale And Registration Rights Agreement                      
Class Of Stock [Line Items]                      
Issuance of Class B common stock in connection with the Acquisition       662,713              
Class A Common Stock                      
Class Of Stock [Line Items]                      
Share conversion, Shares                 810,000 374,000 63,000
Issuance of common stock           1,896          
Silvercrest L.P                      
Class Of Stock [Line Items]                      
Accrued partner incentive allocations                 $ 27,229 $ 27,197 $ 25,101