Non-interest Expenses - Schedule of Components of Noninterest Expense (Footnote) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2014
Schedule Of Non Interest Expense [Line Items]
Write-offs of bad debt		$ 4,400
Provision for bad debts			$ 52,300
Goodwill impairment	$ 0	0	54,000
Impairment losses	$ 1,300	$ 1,300
Futures Reporting Unit [Member]
Schedule Of Non Interest Expense [Line Items]
Goodwill impairment			51,900
Futures Reporting Unit [Member] | Customer relationships [Member]
Schedule Of Non Interest Expense [Line Items]
Impairment losses			7,500
International Asset Management Reporting Unit [Member]
Schedule Of Non Interest Expense [Line Items]
Goodwill impairment			2,100
International Asset Management Reporting Unit [Member] | Customer relationships [Member]
Schedule Of Non Interest Expense [Line Items]
Impairment losses			$ 100