Revenues from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Aug. 31, 2018	Aug. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 633,210	$ 1,903,938
Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	628,026	1,887,808
Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5,184	16,130
Americas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	551,403	1,644,633
Americas | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	546,219	1,628,503
Americas | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5,184	16,130
Europe
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	62,914	203,103
Europe | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	62,914	203,103
Europe | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Asia
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	18,893	56,202
Asia | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	18,893	56,202
Asia | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Equities
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	159,693	471,683
Equities | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	159,693	471,683
Equities | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Fixed Income
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,007	10,511
Fixed Income | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,007	10,511
Fixed Income | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Investment banking - Capital markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	277,735	809,884
Investment banking - Capital markets | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	277,735	809,884
Investment banking - Capital markets | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Investment banking - Advisory
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	187,591	595,730
Investment banking - Advisory | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	187,591	595,730
Investment banking - Advisory | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Asset management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5,184	16,130
Asset management | Capital Markets
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Asset management | Asset Management
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 5,184	$ 16,130