Derivative Financial Instruments - Remaining Contract Maturity of Fair Value of OTC Derivative Assets and Liabilities (Details) $ in Thousands	Feb. 28, 2022 USD ($)
OTC Derivative Assets [Abstract]
0 – 12 Months	$ 494,738
1 – 5 Years	207,530
Greater Than 5 Years	84,444
Cross-Maturity Netting	(61,774)
Total OTC derivative assets, net of cross-maturity netting	724,938
Cross product counterparty netting	(8,869)
Total OTC derivative assets included in Financial instruments owned	716,069
OTC Derivative Liabilities [Abstract]
0 – 12 Months	488,015
1 – 5 Years	999,165
Greater Than 5 Years	233,476
Cross-Maturity Netting	(61,774)
Total OTC derivative liabilities, net of cross-maturity netting	1,658,882
Cross product counterparty netting	(8,869)
Total OTC derivative liabilities included in Financial instruments sold, not yet purchased	1,650,013
Exchange traded derivative assets, with fair value	226,900
Cash collateral received	505,500
Exchange traded derivative liabilities, with fair value	7,000
Cash collateral pledged	744,900
Equity options and forwards
OTC Derivative Assets [Abstract]
0 – 12 Months	10,211
1 – 5 Years	2,998
Greater Than 5 Years	0
Cross-Maturity Netting	(4,086)
Total OTC derivative assets, net of cross-maturity netting	9,123
OTC Derivative Liabilities [Abstract]
0 – 12 Months	9,871
1 – 5 Years	534,211
Greater Than 5 Years	33,407
Cross-Maturity Netting	(4,086)
Total OTC derivative liabilities, net of cross-maturity netting	573,403
Credit default swaps
OTC Derivative Assets [Abstract]
0 – 12 Months	0
1 – 5 Years	15
Greater Than 5 Years	0
Cross-Maturity Netting	0
Total OTC derivative assets, net of cross-maturity netting	15
OTC Derivative Liabilities [Abstract]
0 – 12 Months	0
1 – 5 Years	10,236
Greater Than 5 Years	0
Cross-Maturity Netting	0
Total OTC derivative liabilities, net of cross-maturity netting	10,236
Total return swaps
OTC Derivative Assets [Abstract]
0 – 12 Months	80,255
1 – 5 Years	44,438
Greater Than 5 Years	158
Cross-Maturity Netting	(8,263)
Total OTC derivative assets, net of cross-maturity netting	116,588
OTC Derivative Liabilities [Abstract]
0 – 12 Months	124,832
1 – 5 Years	324,482
Greater Than 5 Years	0
Cross-Maturity Netting	(8,263)
Total OTC derivative liabilities, net of cross-maturity netting	441,051
Foreign currency forwards, swaps and options
OTC Derivative Assets [Abstract]
0 – 12 Months	339,685
1 – 5 Years	4,081
Greater Than 5 Years	0
Cross-Maturity Netting	(4,111)
Total OTC derivative assets, net of cross-maturity netting	339,655
OTC Derivative Liabilities [Abstract]
0 – 12 Months	307,174
1 – 5 Years	5,271
Greater Than 5 Years	0
Cross-Maturity Netting	(4,111)
Total OTC derivative liabilities, net of cross-maturity netting	308,334
Fixed income forwards
OTC Derivative Assets [Abstract]
0 – 12 Months	5,285
1 – 5 Years	0
Greater Than 5 Years	0
Cross-Maturity Netting	0
Total OTC derivative assets, net of cross-maturity netting	5,285
OTC Derivative Liabilities [Abstract]
0 – 12 Months	2,879
1 – 5 Years	0
Greater Than 5 Years	0
Cross-Maturity Netting	0
Total OTC derivative liabilities, net of cross-maturity netting	2,879
Interest rate swaps, options and forwards
OTC Derivative Assets [Abstract]
0 – 12 Months	59,302
1 – 5 Years	155,998
Greater Than 5 Years	84,286
Cross-Maturity Netting	(45,314)
Total OTC derivative assets, net of cross-maturity netting	254,272
OTC Derivative Liabilities [Abstract]
0 – 12 Months	43,259
1 – 5 Years	124,965
Greater Than 5 Years	200,069
Cross-Maturity Netting	(45,314)
Total OTC derivative liabilities, net of cross-maturity netting	$ 322,979