Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Footnote) (Detail) (USD $)	Feb. 28, 2015	Nov. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of equity options transferred from Level 1 to Level 2 within Financial instruments owned	$ 0	$ 6,100,000
Assets at fair value segregated for regulatory purposes	434,800,000	453,700,000
Fair value of equity options transferred from Level 1 to Level 2 within Financial instruments sold, not yet purchased		6,600,000
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets at fair value segregated for regulatory purposes	$ 810,000,000	$ 545,000,000

Fair value of securities deposited in a reserve account for the exclusive benefit of customers pursuant to regulations.

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

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