Investments of Operating Entities and Consolidated Funds - Lehman Claims (Details) (USD $)														1 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Operating Entities	Dec. 31, 2012 Operating Entities	Mar. 31, 2013 Operating Entities Lehman Claim	Dec. 31, 2012 Operating Entities Lehman Claim	Nov. 30, 2012 Operating Entities Lehman Claim	Nov. 02, 2012 Operating Entities Lehman Claim	Sep. 15, 2008 Operating Entities Lehman Claim	Mar. 31, 2013 Consolidated Funds	Dec. 31, 2012 Consolidated Funds	Mar. 31, 2013 Consolidated Funds Lehman Claim	Dec. 31, 2012 Consolidated Funds Lehman Claim	Feb. 29, 2012 Enterprise Master Lehman Claim	Dec. 31, 2011 Enterprise Master Lehman Claim	Jul. 31, 2010 Enterprise Master Lehman Claim	Jun. 30, 2010 Enterprise Master Lehman Claim	Mar. 31, 2013 Enterprise Master Lehman Claim	Nov. 30, 2012 Enterprise Master Lehman Claim	Nov. 02, 2012 Enterprise Master Lehman Claim	Sep. 15, 2008 Enterprise Master Lehman Claim	Mar. 31, 2013 Enterprise Master Trust Assets	Mar. 31, 2013 Enterprise Master Foreign Denominated Assets	Mar. 31, 2013 Enterprise Master Cash	Mar. 31, 2013 Enterprise LP Lehman Claim
Investment Holdings [Line Items]
Initial value									$ 1,000,000									$ 11,700,000			$ 24,300,000			$ 4,200,000
Claim settlement receivable								900,000												1,300,000
Percent of client's Best Claim																		90.00%
Value of Best Claim																		14,800,000
Dividend percent received							25.20%												25.20%
Dividend amount received							200,000												300,000
Estimated recoverable percent																								86.00%
Assets returned															2,400,000		9,500,000
Proceeds from sale of returned assets																10,700,000
Distributions of proceeds from returned assets														2,900,000
Net Equity Claim																		12,400,000
Other investments	80,452,000	84,930,000	80,452,000	84,930,000	660,000	706,000				193,497,000	204,205,000	15,140,000	14,124,000											3,600,000	15,100,000
Other Investments, claim to trust assets held by LBIE through Lehman Brothers																		10,600,000
Other Investments, initial claim current value																		19,000,000
Claim Resolution Agreement fee																						1.00%	1.00%
Other Investments, not within control of LBIE																							$ 5,200,000
Recoverable claims assigned to variable interest entities																		100.00%