Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.8.0.1
Summary of Significant Accounting Policies - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
USD ($)
Segment
Unit
Dec. 31, 2016
USD ($)
Unit
Dec. 31, 2015
USD ($)
Jun. 26, 2013
Summary Of Significant Accounting Policies [Line Items]          
Number of operating segment | Segment   1      
Cash equivalents, maximum maturity period   90 days      
Equity method investments, unrealized intercompany profit (loss) not eliminated amount   $ 0      
Number of reporting unit | Unit   1 1    
Impairment charges on goodwill   $ 0 $ 0 $ 0  
Corporate tax rate   35.00% 35.00% 35.00%  
Scenario Plan          
Summary Of Significant Accounting Policies [Line Items]          
Corporate tax rate 21.00%        
Equity or Balanced Portfolios          
Summary Of Significant Accounting Policies [Line Items]          
Percentage of asset management fee on threshold limit   1.00%      
Asset under management, threshold limit   $ 10,000,000      
Percentage of asset management fee on balance   0.60%      
Fixed Income Portfolios          
Summary Of Significant Accounting Policies [Line Items]          
Percentage of asset management fee on threshold limit   0.40%      
Asset under management, threshold limit   $ 10,000,000      
Percentage of asset management fee on balance   0.30%      
Municipal Value Strategy          
Summary Of Significant Accounting Policies [Line Items]          
Percentage of income from asset management fee   0.65%      
Minimum          
Summary Of Significant Accounting Policies [Line Items]          
Identifiable finite-lived intangible assets, useful life   3 years      
Minimum | Private Funds          
Summary Of Significant Accounting Policies [Line Items]          
Prior written notice period to terminate investment management agreements   30 days      
Prior written notice period after receiving the affirmative vote, to terminate investment management agreements   60 days      
Percentage of income from asset management fee   0.25%      
Minimum | Non-discretionary Assets          
Summary Of Significant Accounting Policies [Line Items]          
Percentage of income from asset management fee   0.05%      
Maximum          
Summary Of Significant Accounting Policies [Line Items]          
Identifiable finite-lived intangible assets, useful life   20 years      
Maximum | Private Funds          
Summary Of Significant Accounting Policies [Line Items]          
Prior written notice period to terminate investment management agreements   90 days      
Prior written notice period after receiving the affirmative vote, to terminate investment management agreements   90 days      
Percentage of income from asset management fee   1.50%      
Maximum | Non-discretionary Assets          
Summary Of Significant Accounting Policies [Line Items]          
Percentage of income from asset management fee   0.01%      
Leasehold Improvements          
Summary Of Significant Accounting Policies [Line Items]          
Property, plant and equipment, useful life   10 years      
Other Fixed Assets | Minimum          
Summary Of Significant Accounting Policies [Line Items]          
Property, plant and equipment, useful life   3 years      
Other Fixed Assets | Maximum          
Summary Of Significant Accounting Policies [Line Items]          
Property, plant and equipment, useful life   7 years      
Equity Method Investments          
Summary Of Significant Accounting Policies [Line Items]          
Impairment charges related to equity method investments   $ 0 $ 0 $ 0  
Class A Common Stock          
Summary Of Significant Accounting Policies [Line Items]          
Common stock, voting rights   1 vote per share      
Class B Common Stock          
Summary Of Significant Accounting Policies [Line Items]          
Common stock, voting rights   1 vote per share      
Class of share exchangeable to another class   One share of Class A common stock      
Silvercrest L.P | Class A Common Stock          
Summary Of Significant Accounting Policies [Line Items]          
Ownership percentage in a subsidiary   62.00% 62.00%   61.60%
Common stock, voting rights   1 vote per share