Income Taxes (Details Textual) (USD $)	12 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010	Aug. 31, 2012	Nov. 30, 2009
Income Tax Contingency [Line Items]
Accumulated Deferred Investment Tax Credit	$ 7,800,000
Income Taxes (Textual) [Abstract]
Income tax benefit	20,100,000	2,400,000	7,000,000
Deferred Tax Assets, Net	0	(1,152,000)		1,200,000
Reversal of liability for Unrecognized tax benefits		2,600,000	1,600,000
Recognition of federal income tax benefit			5,400,000
Net Increase in valuation allowance recorded against net deferred tax assets	32,300,000	76,700,000	21,100,000
Valuation allowance loss for the year			26,600,000
Period for Carry forward of tax benefits related to deferred tax assets	20 years
Deferred tax assets, operating loss carryforwards, federal	313,500,000
Deferred tax assets, operating loss carryforwards, state and local	129,100,000
Minimum expiration period for state NOLs	2013
Maximum expiration period for state NOLs	2032
Deferred Tax Assets, Tax Credit Carryforwards	80,000,000
Tax Credit Expiration Date Minimum	2015
Tax Credit Expiration Date Maximum	2032
Valuation allowance	(880,113,000)	(847,827,000)
Unrecognized tax benefits that if recognized would affect the Company's annual effective tax rate	1,300,000	1,800,000	6,900,000
Total accrued interest and penalties related to unrecognized income tax benefits	600,000	900,000
Uncertain tax positions	1,000,000	1,000,000
Goss unrecognized tax benefits	2,300,000
Income taxes refunded	22,342,000	213,000	196,868,000
Total deferred tax assets	140,907,000	161,569,000
Goss unrecognized tax benefits	1,671,000	1,899,000	11,308,000		11,024,000
Maximum
Income Tax Contingency [Line Items]
Anticipated Decrease in unrecognized tax benefit during 12 months following current reporting date	1,100,000
Minimum
Income Tax Contingency [Line Items]
Anticipated Decrease in unrecognized tax benefit during 12 months following current reporting date	200,000
Maximum
Income Taxes (Textual) [Abstract]
Expiration year of federal NOL carryforward	2032
Minimum
Income Taxes (Textual) [Abstract]
Expiration year of federal NOL carryforward	2030
Investment Tax Credit Carryforward, Expiration in 2026 [Member]
Income Tax Contingency [Line Items]
Accumulated Deferred Investment Tax Credit	7,000,000
Investment Tax Credit Carryforward, Expiration in 2027 [Member]
Income Tax Contingency [Line Items]
Accumulated Deferred Investment Tax Credit	$ 800,000