Commitments, Contingencies and Guarantees - Additional Information (Detail) $ in Millions	6 Months Ended
May 31, 2017 USD ($)
Loss Contingencies [Line Items]
Loan commitments outstanding to clients	$ 127.4
Fair value of mortgage-related commitments	36.4
Fair value of derivative contracts approximated deemed to meet the definition of a guarantee	149.4
Maximum amount payable under guarantee	0.2
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Letters of credit commitments	$ 58.1
Standby letters of credit expiration period	1 year
Jefferies Capital Partners LLC [Member]
Loss Contingencies [Line Items]
Outstanding equity commitments	$ 22.9
Other Investments [Member]
Loss Contingencies [Line Items]
Outstanding equity commitments	$ 1.5

Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16)(a)(2))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant