Defined Contribution and Deferred Compensation Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Contribution Plan Disclosure [Line Items]
Silvercrest matching contributions towards benefit of employees	$ 19	$ 26	$ 56	$ 80
Defined contribution plan, plan name			401(k) savings plan
Maximum
Defined Contribution Plan Disclosure [Line Items]
Silvercrest matching contribution percentage			4.00%