Fair Value Disclosures - Summary of Valuation Bases (Pricing Information) for Financial Instruments (Detail)	Feb. 28, 2015	Nov. 30, 2014
Financial Instruments Owned And Sold Not Yet Purchased Measured Using Different Valuation Basis [Line Items]
Financial Instruments Owned	100.00%	100.00%
Financial Instruments Sold, Not Yet Purchased	100.00%	100.00%
Exchange closing prices [Member]
Financial Instruments Owned And Sold Not Yet Purchased Measured Using Different Valuation Basis [Line Items]
Financial Instruments Owned	11.00%	12.00%
Financial Instruments Sold, Not Yet Purchased	25.00%	20.00%
Recently observed transaction prices [Member]
Financial Instruments Owned And Sold Not Yet Purchased Measured Using Different Valuation Basis [Line Items]
Financial Instruments Owned	4.00%	4.00%
Financial Instruments Sold, Not Yet Purchased	3.00%	2.00%
External pricing services [Member]
Financial Instruments Owned And Sold Not Yet Purchased Measured Using Different Valuation Basis [Line Items]
Financial Instruments Owned	73.00%	71.00%
Financial Instruments Sold, Not Yet Purchased	64.00%	69.00%
Broker quotes [Member]
Financial Instruments Owned And Sold Not Yet Purchased Measured Using Different Valuation Basis [Line Items]
Financial Instruments Owned	4.00%	4.00%
Financial Instruments Sold, Not Yet Purchased	4.00%	3.00%
Valuation techniques [Member]
Financial Instruments Owned And Sold Not Yet Purchased Measured Using Different Valuation Basis [Line Items]
Financial Instruments Owned	8.00%	9.00%
Financial Instruments Sold, Not Yet Purchased	4.00%	6.00%