Loans to and Investments In Associated Companies (Schedule Of Loans to and Investments In Associated Companies) (Details) - USD ($) $ in Thousands	3 Months Ended
Feb. 29, 2020	Feb. 28, 2019
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	$ 1,652,957	$ 2,417,332
Income (losses) related to associated companies	(67,855)	27,313
Income (losses) related to Jefferies associated companies	28,759	11,337
Contributions to (distributions from) associated companies, net	(60,517)	(75,961)
Other	9,284	1,005
Loans to and investments in associated companies as of end of period	1,562,628	2,381,026
Jefferies Finance
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	673,867	728,560
Income (losses) related to associated companies	0	0
Income (losses) related to Jefferies associated companies	5,119	(6,999)
Contributions to (distributions from) associated companies, net	4,871	(71,348)
Other	0	0
Loans to and investments in associated companies as of end of period	683,857	650,213
Berkadia
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	268,949	245,228
Income (losses) related to associated companies	0	0
Income (losses) related to Jefferies associated companies	21,894	22,649
Contributions to (distributions from) associated companies, net	(36,165)	(17,323)
Other	305	172
Loans to and investments in associated companies as of end of period	254,983	250,726
FXCM
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	70,223	75,031
Income (losses) related to associated companies	(1,638)	(2,716)
Income (losses) related to Jefferies associated companies	0	0
Contributions to (distributions from) associated companies, net	0	0
Other	(144)	187
Loans to and investments in associated companies as of end of period	68,441	72,502
Linkem
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	194,847	165,157
Income (losses) related to associated companies	(13,185)	(1,621)
Income (losses) related to Jefferies associated companies	0	0
Contributions to (distributions from) associated companies, net	(359)	32,578
Other	(113)	1,030
Loans to and investments in associated companies as of end of period	181,190	197,144
Real estate associated companies
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	255,309	87,074
Income (losses) related to associated companies	(53,014)	2,596
Income (losses) related to Jefferies associated companies	0	0
Contributions to (distributions from) associated companies, net	(29,415)	0
Other	0	0
Loans to and investments in associated companies as of end of period	172,880	89,670
Other
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	189,762	125,110
Income (losses) related to associated companies	(18)	(34)
Income (losses) related to Jefferies associated companies	1,746	(4,313)
Contributions to (distributions from) associated companies, net	551	5,728
Other	9,236	(387)
Loans to and investments in associated companies as of end of period	201,277	126,104
National Beef
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period		653,630
Income (losses) related to associated companies	0	27,105
Income (losses) related to Jefferies associated companies		0
Contributions to (distributions from) associated companies, net		(25,596)
Other		3
Loans to and investments in associated companies as of end of period		655,142
HomeFed
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period		337,542
Income (losses) related to associated companies	0	1,983
Income (losses) related to Jefferies associated companies		0
Contributions to (distributions from) associated companies, net		0
Other		0
Loans to and investments in associated companies as of end of period		$ 339,525
Linkem and Other \| Loans and debt securities
Equity Method Investment [Roll Forward]
Loans to and investments in associated companies as of beginning of period	70,200
Loans to and investments in associated companies as of end of period	75,100
RedSky JZ Fulton Mall
Equity Method Investment [Roll Forward]
Equity method investment, other than temporary impairment	$ 55,600

Equity Method Investment [Roll Forward]

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