Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2010
Cash Flows From Operating Activities:
Net income	$ 264,768	$ 227,574	$ 201,225
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,085	25,269	24,911
Amortization of deferred sales commissions	20,480	35,723	35,518
Stock-based compensation	56,027	52,030	47,858
Deferred income taxes	(11,478)	54,868	(16,504)
Net gains on investments and derivatives	(10,957)	(11,931)	(7,150)
Equity in net income of affiliates, net of amortization	(4,161)	(4,898)	(848)
Dividends received from affiliates	11,369	1,608	1,313
Consolidated CLO entity operating activities:
Net (gains) losses on bank loans, other investments and note obligations	(22,648)	38,153	0
Amortization of investments	(1,014)	(1,221)	0
Net decrease in other assets and liabilities, including cash	(23,060)	(3,122)	0
Changes in operating assets and liabilities:
Investment advisory fees and other receivables	(2,735)	456	(21,651)
Investments in trading securities	(142,862)	(214,826)	(208,793)
Deferred sales commissions	(11,933)	(15,505)	(31,696)
Other assets	(5,049)	(38,948)	(15,397)
Accrued compensation	7,944	17,471	34,692
Accounts payable and accrued expenses	7,549	(7,406)	9,937
Other liabilities	20,453	17,017	42,484
Net cash provided by operating activities	178,778	172,312	95,899
Cash Flows From Investing Activities:
Additions to equipment and leasehold improvements	(4,109)	(10,639)	(12,205)
Net cash paid in acquisition	(12,334)	(11,595)	(8,797)
Cash paid for intangible assets	(200)	(1,650)	0
Payments received on note receivable from affiliate	0	0	8,000
Proceeds from sales of investments	82,422	158,439	40,497
Purchase of investments	(209,870)	(1,569)	(41,520)
Consolidated CLO entity investing activities:
Proceeds from sales and maturities of bank loans and other investments	169,099	291,381	0
Purchase of bank loans and other investments	(115,913)	(290,847)	0
Net cash (used for) provided by investing activities	(90,905)	133,520	(14,025)
Cash Flows From Financing Activities:
Purchase of additional non-controlling interest	(19,864)	(6,611)	(11,244)
Proceeds from issuance of Voting Common Stock	56	0	0
Proceeds from issuance of Non-Voting Common Stock	55,711	60,941	56,237
Repurchase of Voting Common Stock	0	0	(96)
Repurchase of Non-Voting Common Stock	(106,470)	(198,627)	(111,173)
Principal repayments on notes receivable from stock option exercises	821	941	1,864
Excess tax benefit of stock option exercises	8,618	7,022	10,825
Dividends paid	(87,826)	(85,240)	(75,651)
Line of credit issuance costs	(1,192)	0	0
Net subscriptions received from (redemptions/distributions paid to) non-controlling interest holders	42,012	118,527	44,986
Consolidated CLO Entity Financing Activities:
Principal repayments of senior notes	(28,614)
Net cash used for financing activities	(136,748)	(103,047)	(84,252)
Effect of currency rate changes on cash and cash equivalents	38	242	(322)
Net (decrease) increase in cash and cash equivalents	(48,837)	203,027	(2,700)
Cash and cash equivalents, beginning of period	510,913	307,886	310,586
Cash and cash equivalents, end of period	462,076	510,913	307,886
Supplemental Cash Flow Information:
Cash paid for interest	32,772	32,642	32,642
Cash paid for interest by consolidated CLO entity	19,508	11,100	0
Cash paid for income taxes, net of refunds	152,730	83,610	135,853
Supplemental Disclosure of Non-Cash Information:
Increase in equipment and leasehold improvements due to non-cash additions	513	3,350	860
Exercise of stock options through issuance of notes receivable	535	2,224	1,944
Consolidation of CLO Entity:
Increase in other assets, net of other liabilities	0	10,418	0
Increase in investments	0	446,440	0
Increase in borrowings	0	446,192	0
Deconsolidations of Sponsored Investment Funds:
Decrease in investments	(66,778)	(124,253)	(52,594)
Decrease in non-controlling interests	$ (65,092)	$ (125,844)	$ (36,372)