Consolidated Sponsored Investment Products - Balances of Consolidated Sponsored Investment Products (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Total cash	$ 12,319	$ 531
Total investments	207,279	139,054
All other assets	3,285	9,595
Total liabilities	(16,011)	(8,435)
Redeemable noncontrolling interests	(10,397)	(42,186)
Company's net interests in consolidated sponsored investment products	$ 196,475	$ 98,559

Carrying amount, attributable to parent and noncontrolling interests, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

No definition available.

Name:	us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant