Goodwill and Other Intangible Assets - Gross Cost and Accumulated Amortization of Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Intangible Assets [Line Items]
Other intangible assets, Gross Cost	$ 63,804	$ 63,803
Other intangible assets, Accumulated Amortization	46,599	45,379
Other intangible assets, Net Carrying Amount	17,205	18,424
Success\Performance Fees [Member]
Intangible Assets [Line Items]
Other intangible assets, Gross Cost	30,740	30,740
Other intangible assets, Accumulated Amortization	17,687	17,173
Other intangible assets, Net Carrying Amount	13,053	13,567
Management Fees, Customer Relationships and Non-Compete Agreements [Member]
Intangible Assets [Line Items]
Other intangible assets, Gross Cost	33,064	33,063
Other intangible assets, Accumulated Amortization	28,912	28,206
Other intangible assets, Net Carrying Amount	$ 4,152	$ 4,857