Summary of Significant Accounting Policies (Basic and Diluted Loss Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Numerator:
Net loss	$ 7,724	$ 3,261	$ (24,136)	$ (45,802)	$ 13,911	$ (9,649)	$ (68,504)	$ (114,526)	$ (58,953)	$ (178,768)	$ (69,368)
Denominator:
Basic and diluted average shares outstanding									77,106	77,043	76,889
Basic and diluted loss per share	$ 0.10	$ 0.04	$ (0.31)	$ (0.59)	$ 0.18	$ (0.13)	$ (0.89)	$ (1.49)	$ (0.76)	$ (2.32)	$ (0.90)