Derivative Financial Instruments - Remaining Contract Maturity of Fair Value of OTC Derivative Assets and Liabilities (Details) $ in Thousands	May 31, 2022 USD ($)
OTC Derivative Assets [Abstract]
0 – 12 Months	$ 303,712
1 – 5 Years	398,188
Greater Than 5 Years	34,104
Cross-Maturity Netting	(142,503)
Total OTC derivative assets, net of cross-maturity netting	593,501
Cross product counterparty netting	(19,797)
Total OTC derivative assets included in Financial instruments owned	573,704
OTC Derivative Liabilities [Abstract]
0 – 12 Months	612,279
1 – 5 Years	871,651
Greater Than 5 Years	460,143
Cross-Maturity Netting	(142,503)
Total OTC derivative liabilities, net of cross-maturity netting	1,801,570
Cross product counterparty netting	(19,797)
Total OTC derivative liabilities included in Financial instruments sold, not yet purchased	1,781,773
Exchange traded derivative assets, with fair value	249,900
Cash collateral received	415,500
Exchange traded derivative liabilities, with fair value	25,500
Cash collateral pledged	571,600
Equity options and forwards
OTC Derivative Assets [Abstract]
0 – 12 Months	15,292
1 – 5 Years	3,514
Greater Than 5 Years	0
Cross-Maturity Netting	(14,945)
Total OTC derivative assets, net of cross-maturity netting	3,861
OTC Derivative Liabilities [Abstract]
0 – 12 Months	78,364
1 – 5 Years	393,463
Greater Than 5 Years	22,849
Cross-Maturity Netting	(14,945)
Total OTC derivative liabilities, net of cross-maturity netting	479,731
Credit default swaps
OTC Derivative Assets [Abstract]
0 – 12 Months	0
1 – 5 Years	8
Greater Than 5 Years	4,177
Cross-Maturity Netting	(8)
Total OTC derivative assets, net of cross-maturity netting	4,177
OTC Derivative Liabilities [Abstract]
0 – 12 Months	0
1 – 5 Years	594
Greater Than 5 Years	8,717
Cross-Maturity Netting	(8)
Total OTC derivative liabilities, net of cross-maturity netting	9,303
Total return swaps
OTC Derivative Assets [Abstract]
0 – 12 Months	69,436
1 – 5 Years	39,246
Greater Than 5 Years	46
Cross-Maturity Netting	(9,812)
Total OTC derivative assets, net of cross-maturity netting	98,916
OTC Derivative Liabilities [Abstract]
0 – 12 Months	387,018
1 – 5 Years	122,606
Greater Than 5 Years	100
Cross-Maturity Netting	(9,812)
Total OTC derivative liabilities, net of cross-maturity netting	499,912
Foreign currency forwards, swaps and options
OTC Derivative Assets [Abstract]
0 – 12 Months	120,957
1 – 5 Years	3,836
Greater Than 5 Years	284
Cross-Maturity Netting	(3,128)
Total OTC derivative assets, net of cross-maturity netting	121,949
OTC Derivative Liabilities [Abstract]
0 – 12 Months	81,886
1 – 5 Years	3,192
Greater Than 5 Years	49
Cross-Maturity Netting	(3,128)
Total OTC derivative liabilities, net of cross-maturity netting	81,999
Fixed income forwards
OTC Derivative Assets [Abstract]
0 – 12 Months	30,634
1 – 5 Years	0
Greater Than 5 Years	0
Cross-Maturity Netting	0
Total OTC derivative assets, net of cross-maturity netting	30,634
OTC Derivative Liabilities [Abstract]
0 – 12 Months	845
1 – 5 Years	0
Greater Than 5 Years	0
Cross-Maturity Netting	0
Total OTC derivative liabilities, net of cross-maturity netting	845
Interest rate swaps, options and forwards
OTC Derivative Assets [Abstract]
0 – 12 Months	67,393
1 – 5 Years	351,584
Greater Than 5 Years	29,597
Cross-Maturity Netting	(114,610)
Total OTC derivative assets, net of cross-maturity netting	333,964
OTC Derivative Liabilities [Abstract]
0 – 12 Months	64,166
1 – 5 Years	351,796
Greater Than 5 Years	428,428
Cross-Maturity Netting	(114,610)
Total OTC derivative liabilities, net of cross-maturity netting	$ 729,780