Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash Flows From Operating Activities
Net Income	$ 68,262	$ 48,643
Adjustments to Reconcile Net Income to Net Cash Provided by (Used In) Operating Activities:
Net (Gains) Losses on Investments, Marketable Securities and Contingent Consideration	(904)	(2,790)
Equity Method Investments	5,620	4,041
Equity-Based and Other Deferred Compensation	82,857	92,313
Depreciation, Amortization and Accretion	12,716	12,237
Bad Debt Expense	1,582	417
Deferred Taxes	15,984	1,608
Decrease (Increase) in Operating Assets:
Marketable Securities	400	166
Financial Instruments Owned and Pledged as Collateral at Fair Value	(40,853)	35,540
Securities Purchased Under Agreements to Resell	13,803	(7,333)
Accounts Receivable	(24,583)	28,172
Receivable from Employees and Related Parties	(2,973)	(5,018)
Other Assets	(29,279)	(17,955)
(Decrease) Increase in Operating Liabilities:
Accrued Compensation and Benefits	(47,708)	(31,204)
Accounts Payable and Accrued Expenses	11,638	272
Securities Sold Under Agreements to Repurchase	27,050	(28,228)
Payables to Employees and Related Parties	(6,998)	1,989
Taxes Payable	(4,145)	(12,440)
Other Liabilities	6,782	(1,628)
Net Cash Provided by Operating Activities	89,251	118,802
Cash Flows From Investing Activities
Investments Purchased	(10,783)	(2,327)
Distributions of Private Equity Investments	216	1,175
Marketable Securities:
Proceeds from Sales and Maturities	31,999	26,739
Purchases	(16,549)	(29,141)
Cash Acquired from Acquisitions	0	66
Purchase of Furniture, Equipment and Leasehold Improvements	(10,223)	(1,988)
Net Cash Provided by (Used in) Investing Activities	(5,340)	(5,476)
Cash Flows From Financing Activities
Issuance of Noncontrolling Interests	2,135	3,189
Distributions to Noncontrolling Interests	(8,553)	(17,341)
Cash Paid for Deferred and Contingent Consideration	(2,255)	0
Short-Term Borrowing	75,000	0
Repayment of Short-Term Borrowing	(75,000)	0
Purchase of Treasury Stock and Noncontrolling Interests	(137,443)	(99,730)
Excess Tax Benefits Associated with Equity-Based Awards	33,045	7,720
Dividends - Class A Stockholders	(27,911)	(21,214)
Net Cash Provided by (Used in) Financing Activities	(140,982)	(127,376)
Effect of Exchange Rate Changes on Cash	(2,313)	(1,583)
Net Increase (Decrease) in Cash and Cash Equivalents	(59,384)	(15,633)
Cash and Cash Equivalents-Beginning of Period	298,453	259,431
Cash and Cash Equivalents-End of Period	239,069	243,798
SUPPLEMENTAL CASH FLOW DISCLOSURE
Payments for Interest	11,518	10,767
Payments for Income Taxes	14,640	50,187
Furniture, Equipment and Leasehold Improvements Accrued	857	621
Increase in Fair Value of Redeemable Noncontrolling Interest	14,616	123
Dividend Equivalents Issued	4,481	4,409
Notes Exchanged for Equity in Subsidiary	0	1,042
Settlement of Contingent Consideration	7,232	2,494
Receipt of Marketable Securities in Settlement of Accounts Receivable	2,083	1,730
Purchase of Noncontrolling Interest	7,100	0
Contingent Consideration Accrued	2,162	0
Adjustments to Redeemable Noncontrolling Interest	$ 31,268	$ 0