Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME	$ 85,429	$ 17,649
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization of property	8,859	8,059
Amortization of deferred expenses, share-based incentive compensation and interest rate hedge	83,023	88,074
Amortization of intangible assets related to acquisitions	1,220	877
(Increase) decrease in operating assets:
Deposits with banks	(29,370)	30,635
Cash deposited with clearing organizations and other segregated cash	(2,284)	2,812
Receivables-net	(9,149)	11,333
Investments	61,090	4,954
Other assets	(102,518)	(77,560)
Increase (decrease) in operating liabilities:
Deposits and other payables	71,680	(13,792)
Accrued compensation and benefits and other liabilities	(114,174)	(146,126)
Net cash provided by (used in) operating activities	53,806	(73,085)
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to property	(3,153)	(29,198)
Disposals of property	250	2,631
Net cash used in investing activities	(2,903)	(26,567)
Proceeds from:
Contributions from noncontrolling interests	384
Excess tax benefits from share-based incentive compensation	1,925	2,211
Payments for:
Capital lease obligations	(583)	(1,004)
Distributions to noncontrolling interests	(4,312)	(2,617)
Purchase of Class A common stock	(106,935)	(30,168)
Class A common stock dividends	(35,917)
Settlement of vested share-based incentive compensation	(82,021)	(116,954)
Other financing activities	(332)
Net cash used in financing activities	(227,791)	(148,532)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	1,995	(15,895)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(174,893)	(264,079)
CASH AND CASH EQUIVALENTS-January 1	841,482	850,190
CASH AND CASH EQUIVALENTS-March 31	$ 666,589	$ 586,111