Income Taxes - Reconciliation of Effective Tax Rate to U.S. Federal Statutory Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2014
Amount
Computed expected income taxes	$ 10,490	$ 39,979	$ 106,058
State and city income taxes, net of Federal income tax benefit	124	(3,542)	20,304
International operations (including foreign rate differential)	(3,404)	(11,474)	(3,061)
Tax exempt income	(4,640)	(6,789)	(6,746)
Non deductible settlements	0	0	3,850
Valuation allowance related to the Jefferies Bache business	0	0	4,655
Goodwill impairment	0	0	13,619
Foreign tax credits	0	(7,240)	(3,149)
Meals and entertainment	4,640	5,232	4,103
Excess stock detriment	9,755	0	0
Federal benefits related to prior year tax filings	(2,928)	199	1,055
Non-deductible Jefferies Bache wind down costs	0	3,225	0
Other, net	529	(692)	1,373
Total income tax expense	$ 14,566	$ 18,898	$ 142,061
Percent
Computed expected income taxes	35.00%	35.00%	35.00%
State and city income taxes, net of Federal income tax benefit	0.50%	(3.10%)	6.70%
International operations (including foreign rate differential)	(11.40%)	(10.00%)	(1.00%)
Tax exempt income	(15.50%)	(5.90%)	(2.20%)
Non deductible settlements	0.00%	0.00%	1.30%
Valuation allowance related to the Jefferies Bache business	0.00%	0.00%	1.50%
Goodwill impairment	0.00%	0.00%	4.50%
Meals and entertainment	15.50%	4.60%	1.40%
Excess stock detriment	32.60%	0.00%	0.00%
Federal benefits related to prior year tax filings	(9.80%)	0.10%	0.30%
Non-deductible Jefferies Bache wind down costs	0.00%	2.80%	0.00%
Foreign tax credits	(0.00%)	(6.30%)	(1.00%)
Other, net	1.70%	(0.70%)	0.40%
Total income taxes	48.60%	16.50%	46.90%