Fair Value Disclosures - Summary of Gains (Losses) Due to Changes in Instrument Specific Credit Risk for Loans and Other Receivables and Loan Commitments Measured at Fair Value under Fair Value Option (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2020	Aug. 31, 2019
Financial instruments owned:
Loans and other receivables	$ 1,704	$ 2,040	$ (11,256)	$ (5,458)
Short-term borrowings
Financial instruments sold, not yet purchased and Long-term debt
Changes in instrument specific credit risk	(23)	0	(92)	0
Other changes in fair value	(1,115)	0	(959)	0
Other secured financings
Financial instruments sold, not yet purchased and Long-term debt
Other changes in fair value	617	0	617	0
Long-term debt
Financial instruments sold, not yet purchased and Long-term debt
Changes in instrument specific credit risk	(177,801)	6,922	49,369	34,414
Other changes in fair value	(9,943)	(46,003)	(78,567)	(93,311)
Loans
Financial instruments sold, not yet purchased and Long-term debt
Changes in instrument specific credit risk	367	0	(610)	0
Loan commitments
Financial instruments sold, not yet purchased and Long-term debt
Changes in instrument specific credit risk	$ 1,875	$ (443)	$ 464	$ (1,200)