Intangible Assets, Net - Summary of Intangible Assets, Net (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Definite-lived intangible assets:
Investment contracts	$ 157,672	$ 157,882
Accumulated amortization	(147,506)	(145,665)
Definite-lived intangible assets, net	10,166	12,217
Indefinite-lived intangible assets	32,416	32,416
Total intangible assets, net	$ 42,582	$ 44,633	$ 46,606	$ 48,711