Goodwill and Intangible Assets, Net - Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 171,367	$ 191,067
Accumulated Amortization	(67,864)	(68,661)
Net Carrying Amount	103,503us-gaap_FiniteLivedIntangibleAssetsNet	122,406us-gaap_FiniteLivedIntangibleAssetsNet
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	139,767	139,767
Accumulated Amortization	(58,910)	(44,398)
Net Carrying Amount	80,857	95,369
Institutional Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	16,600	34,800
Accumulated Amortization	(6,618)	(21,973)
Net Carrying Amount	9,982	12,827
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,000	16,500
Accumulated Amortization	(2,336)	(2,290)
Net Carrying Amount	$ 12,664	$ 14,210

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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