Segment Reporting - Impact of Reclassification on Company's Economic Net Income ("ENI") (Detail) (Total Reportable Segments [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012
Private Equity Segment [Member]
Segment Reporting Information [Line Items]
Impact of Reclassification on Economic Net Income (Loss)	$ (3,623)	$ (6,322)
Credit Segment [Member]
Segment Reporting Information [Line Items]
Impact of Reclassification on Economic Net Income (Loss)	$ 3,623	$ 6,322