Fair Value Measurements for Operating Entities and Consolidated Funds Carrying Value Disclosures (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014	Mar. 10, 2014
Cash and cash equivalents		$ 57,783	$ 158,485	$ 145,707	$ 129,509
Cash collateral pledged		13,772	10,085
Cash and cash equivalents, Consolidated Funds		7,942	13,934
Convertible debt	[1]	126,138	122,401
Notes payable and other debt		104,752	68,565
Convertible Debt
Convertible debt, unamortized discount		21,400	24,700			$ 35,700
Level 1
Cash and cash equivalents, Fair Value		57,783	158,485
Cash and cash equivalents, Consolidated Funds, Fair Value		7,942	13,934
Level 2
Cash collateral pledged, Fair Value		13,772	10,085
Convertible debt, Fair Value	[2]	137,280	144,946
Notes payable and other debt, Fair Value		$ 110,313	$ 71,945

[1] The carrying amount of the convertible debt includes an unamortized discount of $21.4 million and $24.7 million as of June 30, 2016 and December 31, 2015.

[2] The convertible debt include the conversion option and is based on the last broker quote available.