Loans to and Investments in Associated Companies (Activity Related to Other Transactions with Jefferies Finance) (Details) - Jefferies Finance - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2020	Aug. 31, 2019
Investments In Associated Companies [Line Items]
Origination and syndication fee revenues	$ 42.4	$ 44.6	$ 123.9	$ 135.8
Origination fee expenses	3.8	8.2	12.4	21.8
CLO placement fee revenues	1.3	1.0	1.7	2.3
Underwriting fees	0.0	2.9	0.3	3.9
Service fees	$ 13.5	$ 12.3	$ 49.4	$ 50.6

Includes (1) underwriting revenue (the spread between the resale price received and the cost of the securities and related expenses) generated through the purchasing, distributing and reselling of new issues of securities (alternatively, could be a secondary offering of a large block of previously issued securities); and (2) fees earned for mergers, acquisitions, divestitures, restructurings, and other types of financial advisory services.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(b),(d))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

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