Segment Reporting - Net Revenues, Expenses and Total Assets by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2017	May 31, 2016	Nov. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 779,294	$ 719,408	$ 1,574,807	$ 1,018,395
Expenses	663,113	616,811	1,334,427	1,165,674
Earnings (loss) before income taxes	116,181	102,597	240,380	(147,279)
Segment assets	40,079,007		40,079,007		$ 36,941,276
Capital Markets [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	778,600	696,500	1,561,200	959,800
Expenses	651,700	602,300	1,308,400	1,135,400
Earnings (loss) before income taxes	126,900	94,200	252,800	(175,600)
Segment assets	39,139,700		39,139,700		35,931,800
Asset management [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	700	22,900	13,600	58,600
Expenses	11,400	14,500	26,000	30,300
Earnings (loss) before income taxes	(10,700)	$ 8,400	(12,400)	$ 28,300
Segment assets	$ 939,300		$ 939,300		$ 1,009,500