Quarterly report pursuant to Section 13 or 15(d)

Equity - Additional Information (Detail)

v3.10.0.1
Equity - Additional Information (Detail) - USD ($)
$ in Thousands
1 Months Ended 3 Months Ended 9 Months Ended
Sep. 30, 2018
Aug. 31, 2018
Jun. 30, 2018
May 31, 2018
Apr. 30, 2018
Mar. 31, 2018
Jan. 31, 2018
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Class Of Stock [Line Items]                      
Partnership distributions, amount               $ 1,529 $ 1,359 $ 6,541 $ 6,001
Distributions of partner incentive allocations of net income                   $ 24,935 $ 21,177
Class B Common Stock                      
Class Of Stock [Line Items]                      
Share conversion, Shares 17,666 22,285   24,732 20,000         (202,000) (52,000)
Issuance of Class B shares, Shares   241,627 6,289 948           6,000 13,000
Class B Common Stock | Resale And Registration Rights Agreement                      
Class Of Stock [Line Items]                      
Share conversion, Shares 17,666 22,285   24,732 20,000 85,286 31,650        
Class A Common Stock                      
Class Of Stock [Line Items]                      
Share conversion, Shares                   202,000 52,000
Issuance of Class B shares, Shares       1,896              
Silvercrest L.P                      
Class Of Stock [Line Items]                      
Accrued partner incentive allocations               $ 7,154 $ 6,189 $ 21,055 $ 17,667