Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Finite Lived Intangible Assets [Line Items]
Initial payment to acquire restructuring business			$ 8,929	$ 56
Goodwill recorded as a result of acquisition			11,900
Amortization of other intangible assets	$ 2,882	$ 2,845	7,797	$ 8,041
Corporate Finance & Restructuring
Finite Lived Intangible Assets [Line Items]
Initial payment to acquire restructuring business	$ 8,900
Goodwill recorded as a result of acquisition			$ 11,900