Investments Summary of Other Equity Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Equity Method Investment	$ 86,287	$ 76,581
G5 Evercore [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment	20,730	32,756
ABS [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment	41,567	43,825
Atalanta Sosnoff [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment	$ 23,990	$ 0