Segment Information (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2020	Aug. 31, 2019	Nov. 30, 2019
Segment Reporting Information [Line Items]
Net revenues		$ 1,616,170	$ 856,778	$ 4,150,087	$ 2,786,878
Income (loss) before income taxes		412,242	13,263	645,543	246,059
Depreciation and amortization expenses		39,520	39,880	119,356	110,600
Assets	[1]	51,773,988		51,773,988		$ 49,460,234
Parent Company interest
Segment Reporting Information [Line Items]
Income (loss) before income taxes		(14,114)	(14,770)	(39,773)	(44,298)
Reportable Segments
Segment Reporting Information [Line Items]
Net revenues		1,614,151	860,424	4,142,570	2,784,291
Income (loss) before income taxes		424,056	31,631	677,118	287,433
Assets		52,233,140		52,233,140		49,554,729
Reportable Segments | Investment Banking and Capital Markets
Segment Reporting Information [Line Items]
Net revenues		1,274,115	757,362	3,451,776	2,274,884
Income (loss) before income taxes		281,323	86,194	745,814	283,892
Depreciation and amortization expenses		22,225	20,754	61,322	56,672
Assets		43,887,885		43,887,885		40,523,223
Reportable Segments | Asset Management
Segment Reporting Information [Line Items]
Net revenues		118,558	20,341	146,278	95,448
Income (loss) before income taxes		87,604	(7,403)	25,122	2,011
Depreciation and amortization expenses		2,018	512	4,776	1,472
Assets		3,192,277		3,192,277		3,313,716
Reportable Segments | Merchant Banking
Segment Reporting Information [Line Items]
Net revenues		220,887	73,754	532,608	391,825
Income (loss) before income taxes		70,747	(35,381)	(57,592)	48,537
Depreciation and amortization expenses		14,408	17,784	50,627	49,904
Assets		3,225,735		3,225,735		3,285,671
Reportable Segments | Corporate
Segment Reporting Information [Line Items]
Net revenues		591	8,967	11,908	22,134
Income (loss) before income taxes		(15,618)	(11,779)	(36,226)	(47,007)
Depreciation and amortization expenses		869	830	2,631	2,552
Assets		1,927,243		1,927,243		2,432,119
Consolidation adjustments
Segment Reporting Information [Line Items]
Net revenues		2,019	(3,646)	7,517	2,587
Income (loss) before income taxes		2,300	$ (3,598)	8,198	$ 2,924
Assets		$ (459,152)		$ (459,152)		$ (94,495)

[1] Total assets include assets related to variable interest entities of $637.5 million and $645.8 million at August 31, 2020 and November 30, 2019, respectively, and Total liabilities include liabilities related to variable interest entities of $3,377.3 million and $3,071.1 million at August 31, 2020 and November 30, 2019, respectively. See Note 7 for additional information related to variable interest entities.