Revenues from Contracts with Customers - Components of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Feb. 28, 2018	Feb. 28, 2017
Disaggregation Of Revenue [Line Items]
Revenues from contracts with customers	$ 599,509
Total revenues	1,086,595	$ 1,009,797
Commissions and other fees
Disaggregation Of Revenue [Line Items]
Revenues from contracts with customers	147,902
Investment banking
Disaggregation Of Revenue [Line Items]
Revenues from contracts with customers	439,991
Asset management fees
Disaggregation Of Revenue [Line Items]
Revenues from contracts with customers	4,930
Other
Disaggregation Of Revenue [Line Items]
Revenues from contracts with customers	6,686
Principal transactions
Disaggregation Of Revenue [Line Items]
Other sources of revenue	217,473
Interest
Disaggregation Of Revenue [Line Items]
Other sources of revenue	257,816
Other
Disaggregation Of Revenue [Line Items]
Other sources of revenue	$ 11,797