Derivative Financial Instruments - Remaining Contract Maturity of Fair Value of OTC Derivative Assets and Liabilities (Detail) $ in Thousands	Nov. 30, 2017 USD ($)
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	$ 142,201
OTC derivative assets having maturity period of 1 to 5 years	174,404
OTC derivative assets having maturity period of greater than 5 years	83,558
OTC derivative assets cross-maturity netting	(89,382)
Total OTC derivative assets, net of cross-maturity netting	310,781
Cross product counterparty netting	(23,732)
Total OTC derivative assets included in Financial instruments owned	287,049
OTC derivative liabilities having maturity period of 0 to 12 months	114,032
OTC derivative liabilities having maturity period of 1 to 5 years	286,786
OTC derivative liabilities having maturity period of greater than 5 years	158,497
OTC derivative liabilities cross-maturity netting	(89,382)
Total OTC derivative liabilities, net of cross-maturity netting	469,933
Cross product counterparty netting	(23,732)
Total OTC derivative liabilities included in Financial instruments sold, not yet purchased	446,201
Exchange traded derivative assets	22,700
Cash collateral received	146,000
Exchange traded derivative liabilities, with fair value	108,700
Cash collateral pledged	318,000
Equity swaps and options
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	3,082
OTC derivative assets having maturity period of 1 to 5 years	6,084
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	0
Total OTC derivative assets, net of cross-maturity netting	9,166
OTC derivative liabilities having maturity period of 0 to 12 months	78
OTC derivative liabilities having maturity period of 1 to 5 years	172,088
OTC derivative liabilities having maturity period of greater than 5 years	2,920
OTC derivative liabilities cross-maturity netting	0
Total OTC derivative liabilities, net of cross-maturity netting	175,086
Credit default swaps
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	567
OTC derivative assets having maturity period of 1 to 5 years	105
OTC derivative assets having maturity period of greater than 5 years	9,510
OTC derivative assets cross-maturity netting	(5,625)
Total OTC derivative assets, net of cross-maturity netting	4,557
OTC derivative liabilities having maturity period of 0 to 12 months	104
OTC derivative liabilities having maturity period of 1 to 5 years	16,540
OTC derivative liabilities having maturity period of greater than 5 years	3,953
OTC derivative liabilities cross-maturity netting	(5,625)
Total OTC derivative liabilities, net of cross-maturity netting	14,972
Total return swaps
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	34,228
OTC derivative assets having maturity period of 1 to 5 years	1,581
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	(193)
Total OTC derivative assets, net of cross-maturity netting	35,616
OTC derivative liabilities having maturity period of 0 to 12 months	28,920
OTC derivative liabilities having maturity period of 1 to 5 years	1,517
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	(193)
Total OTC derivative liabilities, net of cross-maturity netting	30,244
Foreign currency forwards, swaps and options
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	76,213
OTC derivative assets having maturity period of 1 to 5 years	231
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	(30)
Total OTC derivative assets, net of cross-maturity netting	76,414
OTC derivative liabilities having maturity period of 0 to 12 months	59,874
OTC derivative liabilities having maturity period of 1 to 5 years	157
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	(30)
Total OTC derivative liabilities, net of cross-maturity netting	60,001
Fixed income forwards
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative liabilities having maturity period of 0 to 12 months	8,512
OTC derivative liabilities having maturity period of 1 to 5 years	0
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	0
Total OTC derivative liabilities, net of cross-maturity netting	8,512
Interest rate swaps, options and forwards
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	28,111
OTC derivative assets having maturity period of 1 to 5 years	166,403
OTC derivative assets having maturity period of greater than 5 years	74,048
OTC derivative assets cross-maturity netting	(83,534)
Total OTC derivative assets, net of cross-maturity netting	185,028
OTC derivative liabilities having maturity period of 0 to 12 months	16,544
OTC derivative liabilities having maturity period of 1 to 5 years	96,484
OTC derivative liabilities having maturity period of greater than 5 years	151,624
OTC derivative liabilities cross-maturity netting	(83,534)
Total OTC derivative liabilities, net of cross-maturity netting	$ 181,118