Goodwill and Other Intangible Assets - Summary of Intangible Assets, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Definite-lived intangible assets, net:
Investment contracts	$ 158,747	$ 158,747
Accumulated amortization	(152,676)	(149,380)
Definite-lived intangible assets, net	6,071	9,367
Indefinite-lived intangible assets	34,816	32,416
Total intangible assets, net	$ 40,887	$ 41,783	$ 44,633	$ 48,711