Derivative Financial Instruments - Remaining Contract Maturity of Fair Value of OTC Derivative Assets and Liabilities (Detail) $ in Thousands	Nov. 30, 2016 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	$ 263,290
OTC derivative assets having maturity period of 1 to 5 years	235,799
OTC derivative assets having maturity period of greater than 5 years	137,970
OTC derivative assets cross-maturity netting	(83,939)
Total OTC derivative assets, net of cross-maturity netting	553,120
Cross product counterparty netting	(623)
Total OTC derivative assets included in Financial instruments owned	552,497
OTC derivative liabilities having maturity period of 0 to 12 months	226,958
OTC derivative liabilities having maturity period of 1 to 5 years	172,341
OTC derivative liabilities having maturity period of greater than 5 years	99,176
OTC derivative liabilities cross-maturity netting	(83,939)
Total OTC derivative liabilities, net of cross-maturity netting	414,536
Cross product counterparty netting	(623)
Total OTC derivative liabilities included in Financial instruments sold, not yet purchased	413,913
Equity swaps and options [Member]
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	27,436
OTC derivative assets having maturity period of 1 to 5 years	5,727
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	33,163
OTC derivative liabilities having maturity period of 0 to 12 months	10,993
OTC derivative liabilities having maturity period of 1 to 5 years	20,354
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	31,347
Credit default swaps [Member]
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	0
OTC derivative assets having maturity period of 1 to 5 years	4,542
OTC derivative assets having maturity period of greater than 5 years	3,463
OTC derivative assets cross-maturity netting	(1,588)
Total OTC derivative assets, net of cross-maturity netting	6,417
OTC derivative liabilities having maturity period of 0 to 12 months	16
OTC derivative liabilities having maturity period of 1 to 5 years	1,594
OTC derivative liabilities having maturity period of greater than 5 years	7,147
OTC derivative liabilities cross-maturity netting	(1,588)
Total OTC derivative liabilities, net of cross-maturity netting	7,169
Total return swaps [Member]
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	20,749
OTC derivative assets having maturity period of 1 to 5 years	389
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	(200)
Total OTC derivative assets, net of cross-maturity netting	20,938
OTC derivative liabilities having maturity period of 0 to 12 months	12,088
OTC derivative liabilities having maturity period of 1 to 5 years	2,407
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	(200)
Total OTC derivative liabilities, net of cross-maturity netting	14,295
Foreign currency forwards, swaps and options [Member]
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	95,052
OTC derivative assets having maturity period of 1 to 5 years	35,988
OTC derivative assets having maturity period of greater than 5 years	0
OTC derivative assets cross-maturity netting	(10,547)
Total OTC derivative assets, net of cross-maturity netting	120,493
OTC derivative liabilities having maturity period of 0 to 12 months	92,375
OTC derivative liabilities having maturity period of 1 to 5 years	26,011
OTC derivative liabilities having maturity period of greater than 5 years	0
OTC derivative liabilities cross-maturity netting	(10,547)
Total OTC derivative liabilities, net of cross-maturity netting	107,839
Fixed income forwards [Member]
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	3,401
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	3,401
Interest rate swaps, options and forwards [Member]
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	120,053
OTC derivative assets having maturity period of 1 to 5 years	189,153
OTC derivative assets having maturity period of greater than 5 years	134,507
OTC derivative assets cross-maturity netting	(71,604)
Total OTC derivative assets, net of cross-maturity netting	372,109
OTC derivative liabilities having maturity period of 0 to 12 months	108,085
OTC derivative liabilities having maturity period of 1 to 5 years	121,975
OTC derivative liabilities having maturity period of greater than 5 years	92,029
OTC derivative liabilities cross-maturity netting	(71,604)
Total OTC derivative liabilities, net of cross-maturity netting	$ 250,485