Variable Interest Entities ("VIEs") - Variable Interest Entities (Details) - USD ($) $ in Thousands	Jun. 30, 2015		Dec. 31, 2014
Variable Interest Entity [Line Items]
Total VIE Assets	$ 1,979,949	[1]	$ 2,021,915	[2]
Carrying Value of Variable Interest Assets	1,723	[3]	1,611	[4]
Capital Commitments	2		2
Maximum Exposure to Loss in Non- consolidated VIEs	1,725		1,613
Hedge Funds [Member]
Variable Interest Entity [Line Items]
Total VIE Assets	1,904,549	[1]	1,955,515	[2]
Carrying Value of Variable Interest Assets	1,696	[3]	1,584	[4]
Maximum Exposure to Loss in Non- consolidated VIEs	1,696		1,584
Private Equity Funds [Member]
Variable Interest Entity [Line Items]
Total VIE Assets	75,400	[1]	66,400	[2]
Carrying Value of Variable Interest Assets	27	[3]	27	[4]
Capital Commitments	2		2
Maximum Exposure to Loss in Non- consolidated VIEs	$ 29		$ 29

[1] Represents the total assets of the VIEs and does not represent the Company’s interests in the VIEs.

[2] Represents the total assets of the VIEs and does not represent the Company’s interests in the VIEs.

[3] Represents the Company’s interests in the VIEs and is included in other assets on the condensed consolidated balance sheet.

[4] Represents the Company’s interests in the VIEs and is included in other assets on the condensed consolidated balance sheet.