Fair Value Measurements for Operating Entities and Consolidated Funds Carrying Value Disclosures (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Mar. 10, 2014
Cash and cash equivalents		$ 76,925	$ 158,485	$ 92,854	$ 129,509
Cash collateral pledged		13,783	10,085
Cash and cash equivalents, Consolidated Funds		10,370	13,934
Convertible debt	[1]	128,065	122,401
Notes payable and other debt		78,357	68,565
Convertible Debt
Convertible debt, unamortized discount		19,600	24,700			$ 35,700
Level 1
Cash and cash equivalents, Fair Value		76,925	158,485
Cash and cash equivalents, Consolidated Funds, Fair Value		10,370	13,934
Level 2
Cash collateral pledged, Fair Value		13,783	10,085
Convertible debt, Fair Value	[2]	145,676	144,946
Notes payable and other debt, Fair Value		$ 84,257	$ 71,945

[1] The carrying amount of the convertible debt includes an unamortized discount of $19.6 million and $24.7 million as of September 30, 2016 and December 31, 2015.

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