Investments of Operating Entities and Consolidated Funds - Real Estate Investments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investment Holdings [Line Items]
Other investments	$ 84,930	$ 59,943
Operating Entities
Investment Holdings [Line Items]
Other investments	84,930	59,943
Operating Entities | Real Estate Investments
Investment Holdings [Line Items]
Other investments	1,864	2,353
RCG RE Manager, LLC [Member] | Operating Entities | Real Estate Equity Investment [Member]
Investment Holdings [Line Items]
Other investments	1,900	1,600
RCG RE Manager, LLC [Member] | Operating Entities | Real Estate Debt Investment [Member]
Investment Holdings [Line Items]
Other investments	$ 0	$ 800