Fair Value Disclosures - Schedule of Assets and Liabilities Measured on Recurring Basis at Fair Value (Details) - USD ($) $ in Thousands	Nov. 30, 2020	Nov. 30, 2019
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	$ 17,159,193	$ 16,308,807
Counterparty and cash collateral netting, assets	(1,556,136)	(1,433,197)
Loans to and investments in associated companies	48,788
Securities purchased under agreements to resell		25,000
Securities received as collateral, at fair value	7,517	9,500
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	10,017,600	10,532,460
Counterparty and Cash Collateral Netting, liabilities	(1,798,659)	(1,632,178)
Short-term borrowings	5,067	20,981
Other secured financings	1,543
Long-term debt	1,712,245	1,215,285
Obligation to Return Securities Received as Collateral, at Fair Value	7,517	9,500
Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	7,279,781	5,941,623
Loans to and investments in associated companies	0
Securities purchased under agreements to resell		0
Securities received as collateral, at fair value	7,517	9,500
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	5,707,423	5,971,928
Short-term borrowings	0	0
Other secured financings	0
Long-term debt	0	0
Obligation to Return Securities Received as Collateral, at Fair Value	7,517	9,500
Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	10,784,987	11,245,763
Loans to and investments in associated companies	8,603
Securities purchased under agreements to resell		0
Securities received as collateral, at fair value	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	6,039,896	6,086,328
Short-term borrowings	5,067	20,981
Other secured financings	0
Long-term debt	1,036,217	735,216
Obligation to Return Securities Received as Collateral, at Fair Value	0	0
Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	650,561	554,618
Loans to and investments in associated companies	40,185
Securities purchased under agreements to resell		25,000
Securities received as collateral, at fair value	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	68,940	106,382
Short-term borrowings	0	0
Other secured financings	1,543
Long-term debt	676,028	480,069
Obligation to Return Securities Received as Collateral, at Fair Value	0	0
Corporate equity securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,609,950	2,783,993
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	2,059,921	2,767,526
Obligation to Return Securities Received as Collateral, at Fair Value	7,517	0
Corporate equity securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,475,887	2,507,164
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	2,046,441	2,755,601
Corporate equity securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	58,159	218,403
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	9,046	7,438
Corporate equity securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	75,904	58,426
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	4,434	4,487
Corporate debt securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,977,382	2,479,735
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	1,237,772	1,471,482
Obligation to Return Securities Received as Collateral, at Fair Value	0	0
Corporate debt securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
Corporate debt securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,954,236	2,472,245
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	1,237,631	1,471,142
Corporate debt securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	23,146	7,490
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	141	340
Collateralized debt obligations and collateralized loan obligations
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	82,127	153,013
Collateralized debt obligations and collateralized loan obligations | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Collateralized debt obligations and collateralized loan obligations | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	64,155	124,225
Collateralized debt obligations and collateralized loan obligations | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	17,972	28,788
U.S. government and federal agency securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,931,678	2,260,242
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	2,609,660	1,851,981
U.S. government and federal agency securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,840,025	2,101,624
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	2,609,660	1,851,981
U.S. government and federal agency securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	91,653	158,618
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
U.S. government and federal agency securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
Municipal securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	453,881	742,326
Liabilities:
Obligation to Return Securities Received as Collateral, at Fair Value	0	0
Municipal securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Municipal securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	453,881	742,326
Municipal securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Sovereign obligations
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,553,688	2,735,853
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	1,675,511	2,304,540
Obligation to Return Securities Received as Collateral, at Fair Value	0	0
Sovereign obligations | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	1,962,346	1,330,026
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	1,050,771	1,363,475
Sovereign obligations | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	591,342	1,405,827
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	624,740	941,065
Sovereign obligations | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
Residential mortgage-backed securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	1,122,675	1,086,806
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	477
Residential mortgage-backed securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0
Residential mortgage-backed securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	1,100,849	1,069,066
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	477
Residential mortgage-backed securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	21,826	17,740
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0
Commercial mortgage-backed securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	738,294	430,170
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	35	35
Commercial mortgage-backed securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
Commercial mortgage-backed securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	736,291	424,060
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
Commercial mortgage-backed securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,003	6,110
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	35	35
Other asset-backed securities
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	183,606	346,410
Other asset-backed securities | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Other asset-backed securities | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	103,611	303,847
Other asset-backed securities | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	79,995	42,563
Loans and other receivables
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,745,382	2,574,631
Liabilities:
Obligation to Return Securities Received as Collateral, at Fair Value	0	0
Loans and other receivables | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Loans and other receivables | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,610,746	2,460,551
Loans and other receivables | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	134,636	114,080
Loans
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	1,793,081	1,609,691
Loans | Level 1
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	0	0
Loans | Level 2
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	1,776,446	1,600,228
Loans | Level 3
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	16,635	9,463
Derivative, assets
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	481,007	418,408
Derivative, assets | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	1,523	2,809
Derivative, assets | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	2,013,942	1,833,907
Derivative, assets | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	21,678	14,889
Derivative, liabilities
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	641,143	527,205
Derivative, liabilities | Level 1
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	551	871
Derivative, liabilities | Level 2
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	2,391,556	2,066,455
Derivative, liabilities | Level 3
Liabilities:
Total financial instruments sold, not yet purchased, at fair value	47,695	92,057
Investments at fair value
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	220,068	238,100
Investments at fair value | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
Investments at fair value | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	6,122	32,688
Investments at fair value | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	213,946	205,412
FXCM term loan
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	59,455	59,120
FXCM term loan | Level 1
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
FXCM term loan | Level 2
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	0	0
FXCM term loan | Level 3
Assets:
Total financial instruments owned, at fair value, excluding investments at fair value based on NAV	$ 59,455	$ 59,120