Segment Reporting - Adjustments for Compensation and Performance Fees Allocated (Parenthetical) (Detail)	6 Months Ended
	Jun. 30, 2013
Non-Controlling Interest in AlpInvest [Member]
Operating Statistics [Line Items]
Percentage of economic interest	60.00%
Emerging Sovereign Group LLC [Member] | Claren Road [Member]
Operating Statistics [Line Items]
Percentage of economic interest	55.00%