Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash Flows From Operating Activities
Net Income	$ 22,279	$ 43,078
Adjustments to Reconcile Net Income to Net Cash Provided by (Used in) Operating Activities:
Net (Gains) Losses on Investments, Marketable Securities and Contingent Consideration	2,313	(1,916)
Equity Method Investments	3,118	6,024
Equity-Based and Other Deferred Compensation	106,139	57,640
Depreciation, Amortization and Accretion	13,846	8,339
Bad Debt Expense	141	716
Deferred Taxes	9,557	10,883
Decrease (Increase) in Operating Assets:
Marketable Securities	310	203
Financial Instruments Owned and Pledged as Collateral at Fair Value	48,004	(20,006)
Securities Purchased Under Agreements to Resell	(26,962)	19,063
Accounts Receivable	9,618	(17,169)
Receivable from Employees and Related Parties	195	(222)
Other Assets	(18,618)	(32,721)
(Decrease) Increase in Operating Liabilities:
Accrued Compensation and Benefits	(113,581)	(90,898)
Accounts Payable and Accrued Expenses	(963)	7,498
Securities Sold Under Agreements to Repurchase	(21,135)	925
Payables to Employees and Related Parties	12,062	(3,606)
Taxes Payable	448	(475)
Other Liabilities	(437)	(30)
Net Cash Provided by (Used in) Operating Activities	46,334	(12,674)
Cash Flows From Investing Activities
Investments Purchased	(224)	(8,107)
Distributions of Private Equity Investments	6,593	108
Marketable Securities:
Proceeds from Sales and Maturities	20,369	20,839
Purchases	(15,704)	(11,743)
Loans Receivable	(3,500)	0
Purchase of Furniture, Equipment and Leasehold Improvements	(7,695)	(5,971)
Net Cash Provided by (Used in) Investing Activities	(161)	(4,874)
Cash Flows From Financing Activities
Issuance of Noncontrolling Interests	307	49
Distributions to Noncontrolling Interests	(10,291)	(6,414)
Short-Term Borrowing	45,000	50,000
Repayment of Short-Term Borrowing	(45,000)	(50,000)
Purchase of Treasury Stock and Noncontrolling Interests	(123,639)	(94,459)
Excess Tax Benefits Associated with Equity-Based Awards	8,877	29,460
Dividends - Class A Stockholders	(22,703)	(17,878)
Net Cash Provided by (Used in) Financing Activities	(147,449)	(89,242)
Effect of Exchange Rate Changes on Cash	(805)	1,433
Net Increase (Decrease) in Cash and Cash Equivalents	(102,081)	(105,357)
Cash and Cash Equivalents-Beginning of Period	352,160	298,453
Cash and Cash Equivalents-End of Period	250,079	193,096
SUPPLEMENTAL CASH FLOW DISCLOSURE
Payments for Interest	8,661	6,400
Payments for Income Taxes	16,841	7,740
Increase (Decrease) in Fair Value of Redeemable Noncontrolling Interest	(610)	3,530
Dividend Equivalents Issued	3,295	3,096
Settlement of Contingent Consideration	0	7,232
Receipt of Securities in Settlement of Accounts Receivable	1,079	63
Purchase of Noncontrolling Interest	1,123	7,100
Contingent Consideration Accrued	5,039	2,243
Reclassification from Redeemable Noncontrolling Interest to Noncontrolling Interest	$ 0	$ 27,477