Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2011	Aug. 31, 2010	Nov. 30, 2010
Income Taxes (Textuals) [Abstract]
Income tax benefit (expense)	$ 0	$ 5,300,000	$ (100,000)	$ 5,000,000
Net Increase (reduction) in valuation allowance	2,500,000	(2,400,000)	73,300,000	31,600,000
Gross valuation allowance increase (reduction)				37,000,000
Net deferred tax assets	1,152,000		1,152,000		1,152,000
Deferred tax asset valuation allowance	844,400,000		844,400,000		771,100,000
Federal income tax benefit from the increased carryback of the Company's net operating loss to offset earnings		5,400,000		5,400,000
Valuation allowance recorded against the net deferred tax assets generated from the loss for the period		3,000,000
Range of amount of reduction to gross unrecognized tax benefits	0		300,000
Total gross unrecognized tax benefits including interest and penalties	6,600,000		6,600,000
Anticipated Decrease in unrecognized tax benefit during 12 months following current reporting date	$ 2,000,000		$ 2,000,000