Investments - Jefferies LoanCore - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2016	Aug. 31, 2015	Nov. 30, 2015	May 31, 2016	Mar. 31, 2016	Feb. 29, 2016
Guarantee Obligations [Line Items]
Equity commitment	$ 600,000		$ 600,000
Jefferies LoanCore, LLC [Member]
Guarantee Obligations [Line Items]
Aggregate commitment						$ 400,000		$ 600,000
Funded portion of equity commitment to subsidiary			89,600		$ 207,400
Equity commitment	$ 194,000		$ 194,000		291,000
Percentage of the Variable Interest Entity's (VIE) voting interest	48.50%		48.50%
Net earnings from equity method investment	$ 13,400	$ 25,100	$ 36,100	$ 61,600
Administrative services provided	47	47	142	143
Receivables under service agreement	$ 16		$ 16		$ 16
Placement fees earned		$ 1,000		$ 1,600
Canada Pension Plan Investment Board [Member] | Jefferies LoanCore, LLC [Member]
Guarantee Obligations [Line Items]
Ownership percentage by third party							24.00%