Investments of Operating Entities and Consolidated Funds - Securities Purchased Under Agreements to Resell or Sold Under Agreements to Repurchase (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Gross	$ 3,657,000		$ 165,945,000
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral	0	[1]	0	[1]
Securities sold under agreements to repurchase	3,657,000		165,945,000
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral	3,657,000	[2]	165,945,000	[2]
Securities sold under agreements to repurchase, net	0		0
Operating Entities | Securities Owned at Fair Value
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Securities pledged by the Company as collateral	4,600,000		173,700,000
Operating Entities | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	3,657,000		165,945,000
Operating Entities | Royal Bank of Canada | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Interest rates on repurchase agreements	1.75%
Securities sold under agreements to repurchase	3,657,000		29,039,000
Operating Entities | Royal Bank of Canada | Minimum | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Interest rates on repurchase agreements			2.12%
Operating Entities | Royal Bank of Canada | Maximum | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Interest rates on repurchase agreements			2.20%
Operating Entities | Barclays Capital Inc | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase			136,906,000
Operating Entities | Barclays Capital Inc | Minimum | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Interest rates on repurchase agreements			(0.05%)
Operating Entities | Barclays Capital Inc | Maximum | Maturity on Demand
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Interest rates on repurchase agreements			0.23%
US Treasury and Government [Member] | Operating Entities | Securities Owned at Fair Value
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Securities pledged by the Company as collateral			137,500,000
Corporate Bonds | Operating Entities | Securities Owned at Fair Value
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]
Securities pledged by the Company as collateral			$ 36,200,000

[1] Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.

[2] Includes the amount of collateral held/posted.