Fair Value Disclosures - Level 3 Rollforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2019
Assets:
Total gains/(losses) (realized and unrealized)	$ 35,200	$ (55,100)	$ (27,100)
Liabilities:
Total gains/(losses) (realized and unrealized)	12,600	82,100	(44,500)
Corporate equity securities
Assets:
Beginning balance	75,797	58,301	51,040
Total gains/(losses) (realized and unrealized)	31,273	(3,961)	(10,380)
Purchases	8,778	31,778	69,065
Sales	(34,307)	(37,706)	(28,159)
Settlements	(49)	0	(18,208)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	(5,410)	27,385	(5,057)
Ending balance	76,082	75,797	58,301
Changes in unrealized gains/(losses) included in earnings for instruments still held	27,124	(652)	(12,821)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Liabilities:
Beginning balance	4,434	4,487	0
Total gains/(losses) (realized and unrealized)	(83)	456	(2,649)
Purchases	(21)	(513)	(4,322)
Sales	318	0	11,458
Settlements	0	0	0
Issuances	0	0	0
Net transfers into/ (out of) Level 3	(13)	4	0
Ending balance	4,635	4,434	4,487
Changes in unrealized gains/ (losses) included in earnings for instruments still held	83	(81)	1,928
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Corporate debt securities
Assets:
Beginning balance	23,146	7,490	9,484
Total gains/(losses) (realized and unrealized)	1,565	83	(4,860)
Purchases	11,161	1,607	8,900
Sales	(7,978)	(391)	(13,854)
Settlements	(1,417)	(602)	(379)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	(14,674)	14,959	8,199
Ending balance	11,803	23,146	7,490
Changes in unrealized gains/(losses) included in earnings for instruments still held	1,724	(270)	(6,176)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Liabilities:
Beginning balance	141	340	522
Total gains/(losses) (realized and unrealized)	1,205	(268)	(381)
Purchases	(815)	(325)	(457)
Sales	0	394	0
Settlements	(49)	0	(524)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	0	0	1,180
Ending balance	482	141	340
Changes in unrealized gains/ (losses) included in earnings for instruments still held	(139)	27	383
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
CDOs and CLOs
Assets:
Beginning balance	10,513	20,081	25,815
Total gains/(losses) (realized and unrealized)	7,264	(5,703)	(2,342)
Purchases	32,618	10,913	49,658
Sales	(19,332)	(14,389)	(38,147)
Settlements	(4,757)	(2,071)	(9,083)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	5,638	1,682	(5,820)
Ending balance	31,944	10,513	20,081
Changes in unrealized gains/(losses) included in earnings for instruments still held	(4,297)	(15,964)	(974)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
RMBS
Assets:
Beginning balance	21,826	17,740	19,603
Total gains/(losses) (realized and unrealized)	(243)	(934)	(1,669)
Purchases	708	7,887	1,954
Sales	(1,183)	(969)	(2,472)
Settlements	(354)	(1,053)	(152)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	(19,277)	(845)	476
Ending balance	1,477	21,826	17,740
Changes in unrealized gains/(losses) included in earnings for instruments still held	(131)	(599)	(530)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
CMBS
Assets:
Beginning balance	2,003	6,110	10,886
Total gains/(losses) (realized and unrealized)	(1,694)	(827)	(2,888)
Purchases	2,445	393	206
Sales	(393)	(1,856)	(2,346)
Settlements	(13)	(1,787)	(5,317)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	(15)	(30)	5,569
Ending balance	2,333	2,003	6,110
Changes in unrealized gains/(losses) included in earnings for instruments still held	(733)	(295)	(2,366)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Liabilities:
Beginning balance	35	35	0
Total gains/(losses) (realized and unrealized)	0	0	35
Purchases	(35)	0	0
Sales	210	35	0
Settlements	0	0	0
Issuances	0	0	0
Net transfers into/ (out of) Level 3	0	(35)	0
Ending balance	210	35	35
Changes in unrealized gains/ (losses) included in earnings for instruments still held	0	0	(35)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Other ABS
Assets:
Beginning balance	79,995	42,563	53,175
Total gains/(losses) (realized and unrealized)	5,335	(3,848)	433
Purchases	65,277	69,701	104,097
Sales	(21,727)	(1,638)	(73,335)
Settlements	(45,397)	(43,072)	(51,374)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	10,041	16,289	9,567
Ending balance	93,524	79,995	42,563
Changes in unrealized gains/(losses) included in earnings for instruments still held	(14,471)	(5,945)	(98)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0
Loans and other receivables
Assets:
Beginning balance	77,042	64,240	46,985
Total gains/(losses) (realized and unrealized)	(1,065)	(20,487)	(5,505)
Purchases	58,993	73,485	57,403
Sales	(61,560)	(36,929)	(48,350)
Settlements	(15,442)	(7,063)	(5,068)
Issuances	0	0	0
Net transfers into/ (out of) Level 3	16,617	3,796	18,775
Ending balance	74,585	77,042	64,240
Changes in unrealized gains/(losses) included in earnings for instruments still held	(4,924)	(18,747)	(3,319)
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Investments at fair value
Assets:
Beginning balance	67,108	75,738	113,831
Total gains/(losses) (realized and unrealized)	(7,260)	(19,396)	113
Purchases	155	28,132	240
Sales	(23,575)	(167)	(38,446)
Settlements	(1,871)	(17,199)	0
Issuances	0	0	0
Net transfers into/ (out of) Level 3	0	0	0
Ending balance	34,557	67,108	75,738
Changes in unrealized gains/(losses) included in earnings for instruments still held	(9,151)	(21,244)	2,964
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Securities purchased under agreements to resell
Assets:
Beginning balance	0	25,000	0
Total gains/(losses) (realized and unrealized)		0	0
Purchases		0	0
Sales		0	0
Settlements		(25,000)	0
Issuances		0	25,000
Net transfers into/ (out of) Level 3		0	0
Ending balance		0	25,000
Changes in unrealized gains/(losses) included in earnings for instruments still held		0	0
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held		0	0
Loans
Liabilities:
Beginning balance	16,635	9,463	6,376
Total gains/(losses) (realized and unrealized)	1,826	(520)	(1,382)
Purchases	(8,549)	(6,061)	(2,573)
Sales	5,673	13,851	6,494
Settlements	0	0	0
Issuances	0	0	0
Net transfers into/ (out of) Level 3	185	(98)	548
Ending balance	15,770	16,635	9,463
Changes in unrealized gains/ (losses) included in earnings for instruments still held	(1,825)	360	1,382
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Net derivatives
Liabilities:
Beginning balance	26,017	77,168	21,614
Total gains/(losses) (realized and unrealized)	7,246	(40)	(21,452)
Purchases	0	(7,446)	(4,323)
Sales	0	19,376	36,144
Settlements	(1,491)	(2,216)	2,227
Issuances	44,453	0	0
Net transfers into/ (out of) Level 3	(8,456)	(60,825)	42,958
Ending balance	67,769	26,017	77,168
Changes in unrealized gains/ (losses) included in earnings for instruments still held	(7,371)	(1,805)	12,098
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	0	0	0
Other secured financings
Liabilities:
Beginning balance	1,543	0
Total gains/(losses) (realized and unrealized)	(649)	(2,475)
Purchases	0	0
Sales	0	0
Settlements	0	0
Issuances	25,011	4,018
Net transfers into/ (out of) Level 3	0	0
Ending balance	25,905	1,543	0
Changes in unrealized gains/ (losses) included in earnings for instruments still held	649	2,475
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held		0
Structured notes
Liabilities:
Beginning balance	676,028	480,069	200,745
Total gains/(losses) (realized and unrealized)	(22,132)	84,930	(18,662)
Purchases	0	0	0
Sales	0	0	0
Settlements	0	(57,088)	(11,250)
Issuances	169,975	248,718	348,275
Net transfers into/ (out of) Level 3	57,861	(80,601)	(39,039)
Ending balance	881,732	676,028	480,069
Changes in unrealized gains/ (losses) included in earnings for instruments still held	85,260	(51,567)	29,656
Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held	$ (63,126)	$ (33,363)	$ (10,993)