Organization and Basis of Presentation (Details 1) (USD $) In Thousands, except Per Share data	3 Months Ended		8 Months Ended	9 Months Ended
	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2010	Aug. 31, 2011
Effects of the adjustments on Consolidated Statement of Earnings
Principal transactions	$ (74,003)	$ 71,044	$ 317,686	$ 391,464
Interest	353,006	239,557	625,725	930,647
Total revenues	794,104	693,030	1,945,432	2,730,898
Interest expense	284,822	175,761	432,995	736,068
Net revenues	509,282	517,269	1,512,437	1,994,830
Net revenues, less mandatorily redeemable preferred interest	523,953	519,806	1,512,463	1,988,647
Floor brokerage and clearing fees	32,959	30,111	84,199	92,475
Total non-interest expenses	468,715	443,308	1,239,369	1,639,993
Earnings before income taxes	55,238	76,498	273,094	348,654
Income tax expense	1,228	33,873	110,277	107,899
Net earnings	54,010	42,625	162,817	240,755
Net earnings to common shareholders	68,275	44,754	160,952	236,232
Earnings per common share:
Basic	$ 0.30	$ 0.22	$ 0.79	$ 1.07
Diluted	$ 0.30	$ 0.22	$ 0.79	$ 1.07
Scenario, Previously Reported [Member]
Effects of the adjustments on Consolidated Statement of Earnings
Principal transactions		74,282	324,037
Interest		152,546	430,902
Total revenues		609,257	1,756,961
Interest expense		89,159	237,493
Net revenues		520,098	1,519,468
Net revenues, less mandatorily redeemable preferred interest		522,635	1,519,494
Floor brokerage and clearing fees		30,244	84,702
Total non-interest expenses		443,441	1,239,874
Earnings before income taxes		79,194	279,620
Income tax expense		35,067	112,960
Net earnings		44,127	166,660
Net earnings to common shareholders		$ 46,256	$ 164,795
Earnings per common share:
Basic		$ 0.23	$ 0.81
Diluted		$ 0.23	$ 0.81