Fair Value Disclosures - Level 3 Rollforwards (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020
Assets:
Total gains/losses (realized and unrealized)	$ 21,800	$ (39,500)	$ 35,300	$ (69,800)
Liabilities:
Total gains/losses (realized and unrealized)	7,000	(124,300)	60,700	(144,700)
Corporate equity securities
Assets:
Beginning balance	83,278	103,643	75,797	58,301
Total gains/losses (realized and unrealized)	12,057	(5,319)	14,329	(12,860)
Purchases	448	36	8,288	2,989
Sales	(24,561)	(68)	(37,297)	(2,017)
Settlements	0	0	0	0
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	502	(22,192)	10,607	29,687
Ending balance	71,724	76,100	71,724	76,100
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(911)	(5,220)	(653)	(12,787)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Liabilities:
Beginning Balance	4,443	4,275	4,434	4,487
Total gains/losses (realized and unrealized)	42	(60)	64	216
Purchases	(23)	0	(23)	(513)
Sales	0	0	0	0
Settlements	0	0	0	0
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	0	(25)	(13)	0
Ending Balance	4,462	4,190	4,462	4,190
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(40)	60	(62)	140
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Corporate debt securities
Assets:
Beginning balance	6,811	25,090	23,146	7,490
Total gains/losses (realized and unrealized)	1,292	(1,480)	2,466	1,560
Purchases	4,116	328	4,370	766
Sales	(5,870)	(365)	(5,960)	(479)
Settlements	(132)	(1)	(132)	(602)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	1,768	1,606	(15,905)	16,443
Ending balance	7,985	25,178	7,985	25,178
For instruments still held, changes in unrealized gains/(losses) included in Earnings	963	(1,464)	1,492	1,190
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Liabilities:
Beginning Balance	1,571	767	141	340
Total gains/losses (realized and unrealized)	(22)	(23)	1,349	(27)
Purchases	(665)	(20)	(563)	(150)
Sales	27	0	0	0
Settlements	0	0	0	0
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	16	(561)	0	0
Ending Balance	927	163	927	163
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(38)	0	(414)	5
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
CDOs and CLOs
Assets:
Beginning balance	25,894	20,952	10,513	20,081
Total gains/losses (realized and unrealized)	6,557	(12,879)	9,695	(14,223)
Purchases	4,287	0	16,510	9,426
Sales	(29,324)	(8,471)	(27,251)	(11,849)
Settlements	(1,072)	(1,673)	(1,142)	(3,193)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	20,124	25,210	18,141	22,897
Ending balance	26,466	23,139	26,466	23,139
For instruments still held, changes in unrealized gains/(losses) included in Earnings	2,888	(16,031)	6,808	(17,115)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
RMBS
Assets:
Beginning balance	21,692	16,970	21,826	17,740
Total gains/losses (realized and unrealized)	205	(1,773)	33	(2,248)
Purchases	0	1,380	799	2,062
Sales	0	0	(784)	0
Settlements	(612)	(7)	(1,126)	(10)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	(15,252)	5,769	(14,715)	4,795
Ending balance	6,033	22,339	6,033	22,339
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(36)	(1,733)	88	(2,195)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
CMBS
Assets:
Beginning balance	2,671	4,264	2,003	6,110
Total gains/losses (realized and unrealized)	201	53	158	(95)
Purchases	0	0	1,119	0
Sales	0	0	(393)	0
Settlements	(1,696)	0	(1,696)	(1,660)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	0	144	(15)	106
Ending balance	1,176	4,461	1,176	4,461
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(824)	53	(740)	(680)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Liabilities:
Beginning Balance	35	35	35	35
Total gains/losses (realized and unrealized)	0	0	0	0
Purchases	(35)	0	(35)	(35)
Sales	35	105	35	140
Settlements	0	0	0	0
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	0	0	0	0
Ending Balance	35	140	35	140
For instruments still held, changes in unrealized gains/(losses) included in Earnings	0	0	0	0
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Other ABS
Assets:
Beginning balance	60,594	41,903	79,995	42,563
Total gains/losses (realized and unrealized)	3,575	(2,380)	6,373	(2,848)
Purchases	12,835	11,038	34,476	33,917
Sales	(1,099)	0	(27,647)	(664)
Settlements	(14,408)	(8,490)	(26,465)	(17,361)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	9,058	43,991	3,823	30,455
Ending balance	70,555	86,062	70,555	86,062
For instruments still held, changes in unrealized gains/(losses) included in Earnings	819	(5,087)	1,158	(7,226)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Loans and other receivables
Assets:
Beginning balance	79,055	54,321	77,042	64,240
Total gains/losses (realized and unrealized)	1,981	(4,891)	4,312	(8,600)
Purchases	26,948	45,984	37,431	66,047
Sales	(8,070)	(46,939)	(50,556)	(76,227)
Settlements	(156)	(128)	(273)	(6,606)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	19,792	20,082	51,594	29,575
Ending balance	119,550	68,429	119,550	68,429
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(127)	(4,847)	878	(11,689)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Investments at fair value
Assets:
Beginning balance	45,472	55,270	67,108	75,738
Total gains/losses (realized and unrealized)	(4,037)	(10,805)	(2,098)	(30,496)
Purchases	133	400	133	18,885
Sales	0	(91)	(23,575)	(168)
Settlements	(1,183)	0	(1,183)	0
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	0	19,185	0	0
Ending balance	40,385	63,959	40,385	63,959
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(4,037)	(10,805)	(3,989)	(30,496)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Loans
Liabilities:
Beginning Balance	14,916	7,859	16,635	9,463
Total gains/losses (realized and unrealized)	(7)	1,015	1,441	1,072
Purchases	(637)	(2,785)	(6,872)	(12,958)
Sales	6,330	3,290	8,817	3,290
Settlements	44	0	0	0
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	(257)	1,295	368	9,807
Ending Balance	20,389	10,674	20,389	10,674
For instruments still held, changes in unrealized gains/(losses) included in Earnings	(167)	(1,015)	(884)	(1,075)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Net derivatives
Liabilities:
Beginning Balance	305,506	110,843	26,017	77,168
Total gains/losses (realized and unrealized)	(8,965)	(32,744)	16,813	(44,729)
Purchases	(36)	(10,810)	(82)	(11,088)
Sales	33,715	33,196	66,304	38,823
Settlements	593	(603)	506	(1,010)
Issuances	0	0	0	0
Net transfers into/ (out of) Level 3	(103,755)	(54,751)	117,500	(14,033)
Ending Balance	227,058	45,131	227,058	45,131
For instruments still held, changes in unrealized gains/(losses) included in Earnings	8,372	32,259	(17,358)	32,211
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0	0	0	0
Other secured financings
Liabilities:
Beginning Balance	2,168		1,543
Total gains/losses (realized and unrealized)	0		0
Purchases	0		0
Sales	0		0
Settlements	0		0
Issuances	325		950
Net transfers into/ (out of) Level 3	0		0
Ending Balance	2,493		2,493
For instruments still held, changes in unrealized gains/(losses) included in Earnings	0		0
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	0		0
Long-term debt
Liabilities:
Beginning Balance	723,115	543,463	676,028	480,069
Total gains/losses (realized and unrealized)	15,986	(92,480)	41,064	(101,267)
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Issuances	28,565	66,916	50,295	175,498
Net transfers into/ (out of) Level 3	27,432	(20,859)	27,711	(57,260)
Ending Balance	795,098	497,040	795,098	497,040
For instruments still held, changes in unrealized gains/(losses) included in Earnings	3,057	664	20,565	(4,802)
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income	$ (19,043)	91,816	$ (61,629)	106,069
Securities purchased under agreements to resell
Assets:
Beginning balance				25,000
Total gains/losses (realized and unrealized)				0
Purchases				0
Sales				0
Settlements				(25,000)
Issuances
Net transfers into/ (out of) Level 3				0
Ending balance		$ 0		0
For instruments still held, changes in unrealized gains/(losses) included in Earnings				0
For instruments still held, changes in unrealized gains/(losses) included in Other comprehensive income				$ 0