Revenues from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2019	Nov. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 2,222,257	$ 2,594,887
Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,205,038	2,573,673
Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	17,219	21,214
Americas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,762,040	2,207,826
Americas | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,751,568	2,186,955
Americas | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,472	20,871
Europe
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	381,158	304,370
Europe | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	374,411	304,027
Europe | Asset Management
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,747	343
Asia
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	79,059	82,691
Asia | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	79,059	82,691
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	662,804	649,631
Equities | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	662,804	649,631
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	13,505	13,839
Fixed Income | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13,505	13,839
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	767,421	820,042
Investment banking - Advisory | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	767,421	820,042
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	761,308	1,090,161
Investment banking - Underwriting | Investment Banking and Capital Markets
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	761,308	1,090,161
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	17,219	21,214
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	$ 17,219	$ 21,214