Employee Benefit and Stock Plans (Details) (USD $)	12 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2009
Stock option transactions
Options outstanding at beginning of year, Options	8,798,613	5,711,701	7,847,402
Granted, Options	1,716,000	3,572,237	1,403,141
Granted, Weighted Average Exercise Price	$ 6.36	$ 18.71	$ 15.44
Exercise of employee stock options, Shares		(28,281)
Exercised, Weighted Average Exercise Price		$ 13.00
Cancelled, Options	(354,217)	(457,044)	(3,538,842)
Cancelled, Weighted Average Exercise Price	$ 21.47	$ 22.05	$ 28.69
Options outstanding at end of year, Options	10,160,396	8,798,613	5,711,701
Options outstanding at end of year, Weighted Average Exercise Price	$ 21.27	$ 24.19	$ 27.39
Options outstanding at beginning of year, Weighted Average Exercise Price	$ 24.19	$ 27.39	$ 30.11
Options exercisable at end of year, options	7,142,568	6,146,605	4,046,027
Options exercisable at end of period, Weighted Average Exercise Price	$ 26.43	$ 28.73	$ 31.05
Options available for grant at end of year, options	2,477,219	21,703	1,714,650