Investments In Associated Companies (Schedule Of Summarized Data For Investments In Associated Companies) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Feb. 29, 2012 Jefferies Group, Inc. [Member]	Feb. 28, 2011 Jefferies Group, Inc. [Member]	Mar. 31, 2012 JHYH [Member]	Mar. 31, 2011 JHYH [Member]	Mar. 31, 2012 Berkadia [Member]	Mar. 31, 2011 Berkadia [Member]
Investments In Associated Companies [Line Items]
Total revenues	$ 1,006,800	$ 966,700	$ 56,900	$ 73,000	$ 95,800	$ 85,600
Income from continuing operations before extraordinary items	77,100	87,300	36,400	47,800	25,900	19,200
Net income	$ 77,100	$ 87,300	$ 36,400	$ 47,800	$ 25,900	$ 19,200