Fair Value Measurements - Summary of Changes in Fair Value of Company's Level 3 Assets (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value Disclosures [Abstract]
Net unrealized gains (losses)	$ 6,032	$ 12,910	$ (3,268)
Sales/disposition of private equity fund investments			$ 49,500

Amount of unrealized gain (loss) recognized in the income statement from investments for which net asset value per share is calculated on unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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Balance Type:	credit
Period Type:	duration