Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Consolidated net income	$ 173,755	$ 35,513	$ 38,360
Adjustments to reconcile consolidated net income to net cash provided by operating activities:
Gain on divestiture and sale of investments, net of tax	(550,759)	(52,471)
Fixed asset depreciation and intangible asset amortization	47,152	50,985	49,281
Employee loan amortization and reserves on employee loans	194,996	35,596	31,785
Equity-based compensation and allocations of net income to limited partnership units and FPUs	433,998	144,447	143,536
Losses on equity investments	9,508	11,775	6,605
Accretion of discount on convertible notes	5,157	4,378	1,808
Recognition of earn-out and related hedges	(39,529)
Recognition of deferred revenue			(4,583)
Impairment of fixed assets	6,101	1,255	785
Impairment of marketable securities		291	4,047
Deferred tax (benefit) provision	(81,989)	(11,550)	1,963
Sublease provision adjustment	318	(2,596)	4,956
Other	1,508	(65)	96
Consolidated net income, adjusted for non-cash and non-operating items	200,216	217,558	278,639
Decrease (increase) in operating assets:
Receivables from broker-dealers, clearing organizations, customers and related broker-dealers	(51,710)	(104,241)	282,941
Loans, forgivable loans and other receivables from employees and partners, net	(49,478)	(63,315)	(70,038)
Accrued commissions receivable, net	(49,542)	37,751	(4,928)
Securities owned	(1,213)	(16,187)	(5,695)
Receivables from related parties	(5,362)	(14,726)	(2,447)
Cash segregated under regulatory requirements	(5,295)	(424)	(570)
Other assets	(73,422)	(2,046)	(10,413)
Increase (decrease) in operating liabilities:
Payables to broker-dealers, clearing organizations, customers and related broker-dealers	48,973	109,596	(293,140)
Payables to related parties	(24,862)	21,000	9,405
Securities sold, not yet purchased	2,031
Accounts payable, accrued and other liabilities	145,167	23,371	(15,438)
Accrued compensation	30,863	(37,137)	(82,972)
Net cash provided by operating activities	166,366	171,200	85,344
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of fixed assets	(22,988)	(36,759)	(27,190)
Capitalization of software development costs	(15,000)	(14,032)	(15,940)
Purchase of equity method investments	(1,748)	(17,501)	(1,749)
Proceeds from sale of investment		52,471
Payments for acquisitions, net of cash acquired	(746)	(31,413)	(46,703)
Proceeds from divestiture, net	575,287
Purchase of marketable securities	(5,361)
Sale of marketable securities		906
Distribution from equity method investments		928
Purchase of notes receivable		(22,000)
Purchase of exchange membership	(1,696)
Capitalization of trademarks, patent defense and registration costs	(995)	(583)	(1,064)
Net cash provided by (used in) investing activities	526,753	(67,983)	(92,646)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from collateralized borrowings		30,983	21,425
Repayments of collateral borrowings	(48,246)	(24,778)	(17,272)
Repayment of Newmark debt			(13,835)
Issuance of convertible notes, net of debt issuance costs			155,620
Issuance of senior notes, net of deferred issuance costs		108,716
Purchase of capped call			(11,392)
Earnings distributions to noncontrolling interests	(98,345)	(92,330)	(84,332)
Redemption of limited partnership interests	(107,191)	(13,491)	(1,841)
Repurchase of limited partnership units	(6,154)
Dividends to stockholders	(91,395)	(90,590)	(77,244)
Proceeds from offering of Class A common stock, net		12,667	15,632
Repurchase of Class A common stock	(15,528)	(337)	(392)
Proceeds from exercises of stock options			8,812
Proceeds from short-term borrowings		90,000	30,000
Repayments of short-term borrowings		(103,600)	(16,400)
Tax impact on delivery of equity awards	4,700		3,357
Cancelation of restricted stock units in satisfaction of withholding tax requirements	(1,216)	(2,280)	(3,580)
Other	32	32	63
Net cash (used in) provided by financing activities	(363,343)	(85,008)	8,621
Effect of exchange rate changes on cash and cash equivalents	(1,266)	487	4,290
Net increase in cash and cash equivalents	328,510	18,696	5,609
Cash and cash equivalents at beginning of period	388,409	369,713	364,104
Cash and cash equivalents at end of period	716,919	388,409	369,713
Supplemental cash information:
Cash paid during the period for taxes	152,105	20,292	16,682
Cash paid during the period for interest	33,175	27,187	20,520
Supplemental non-cash information:
Issuance of Class A common stock upon exchange of limited partnership interests	65,908	90,199	79,115
Donations with respect to Charity Day	5,720	13,401	12,076
Issuance of Class A common stock upon purchase of notes receivable		3,055
Use of notes receivable in business acquisition		25,617
Issuance of Class A and contingent Class A common stock for acquisitions	1,776	9,026	26,778
Issuance of Class A common stock upon exchange of Cantor units			8,407
Issuance of Class B common stock upon exchange of Cantor units			$ 8,407