Derivatives - Fair Values of Derivatives Reported on Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 1,048	$ 2,355
Derivative Liabilities	195,689	208,093
Forward Foreign Currency Exchange Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	1,015	2,355
Derivative Liabilities	1,584	124
Total Return Swaps and Other [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	33
Derivative Liabilities	531	663
LFI and Other Similar Deferred Compensation Arrangements [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 193,574	$ 207,306