Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Aug. 31, 2020	Aug. 31, 2019	May 31, 2019	Aug. 31, 2020	Aug. 31, 2019	Nov. 30, 2019
Income Taxes [Line Items]
Unrecognized tax benefits	$ 374,100			$ 374,100		$ 327,300
Interest included in unrecognized tax benefits	81,400			81,400		67,200
Net deferred tax asset	312,600			312,600		462,500
Income tax provision (benefit)	107,403	$ (36,131)		$ 185,138	$ (522,626)
Effective income tax rate				28.70%
Recognition of accumulated other comprehensive income lodged taxes			$ 544,600	$ 0	$ 544,583
Lodged tax effect			$ 544,600
Jefferies Group
Income Taxes [Line Items]
Unrecognized tax benefits	$ 233,200			$ 233,200		$ 181,200