Revenues from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Feb. 29, 2020	Feb. 28, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 775,941	$ 447,407
Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	771,537	440,738
Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,404	6,669
Americas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	650,049	326,770
Americas | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	649,069	323,389
Americas | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	980	3,381
Europe
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	82,862	103,493
Europe | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	79,438	100,205
Europe | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,424	3,288
Asia
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	43,030	17,144
Asia | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	43,030	17,144
Asia | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Equities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	176,249	152,074
Equities | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	176,249	152,074
Equities | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Fixed income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,286	3,068
Fixed income | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,286	3,068
Fixed income | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Investment banking - Advisory
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	343,158	180,482
Investment banking - Advisory | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	343,158	180,482
Investment banking - Advisory | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Investment banking - Underwriting
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	248,844	105,114
Investment banking - Underwriting | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	248,844	105,114
Investment banking - Underwriting | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Asset management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,404	6,669
Asset management | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0
Asset management | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 4,404	$ 6,669