Derivatives - Fair Values of Derivatives Reported on Condensed Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 4,057	$ 1,993
Derivative Liabilities	179,023	182,223
Forward Foreign Currency Exchange Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	3,937	1,993
Derivative Liabilities	736	2,792
Total Return Swaps and Other [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	120
Derivative Liabilities	3,547	9,043
LFI and Other Similar Deferred Compensation Arrangements [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 174,740	$ 170,388