Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.5.0.2
Stockholders' Equity - Additional Information (Detail) - USD ($)
$ in Thousands
 1 Months Ended 3 Months Ended 9 Months Ended
Aug. 31, 2016
May 31, 2016
Mar. 31, 2016
Feb. 29, 2016
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Class Of Stock [Line Items]                
Partnership distributions, amount         $ 1,345 $ 1,446 $ 5,760 $ 5,571
Distributions of partner incentive allocations of net income             $ 18,827 $ 18,568
Class B Common Stock                
Class Of Stock [Line Items]                
Common stock issued 241,628 9,198   4,911        
Exchange of Class B common stock for Class A common stock             (59,000) (134,000)
Class B Common Stock | Resale And Registration Rights Agreement                
Class Of Stock [Line Items]                
Exchange of Class B common stock for Class A common stock 21,200   38,076          
Silvercrest L.P                
Class Of Stock [Line Items]                
Accrued partner incentive allocations         $ 5,169 $ 5,022 $ 14,197 $ 14,123