Summary of Significant Accounting Policies (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Nov. 30, 2011	Aug. 31, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Aug. 31, 2010	May 31, 2010	Feb. 28, 2010	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2009
Numerator:
Net loss	$ 13,911	$ (9,649)	$ (68,504)	$ (114,526)	$ 17,442	$ (1,397)	$ (30,709)	$ (54,704)	$ (178,768)	$ (69,368)	$ (101,784)
Denominator:
Basic and diluted average shares outstanding									77,043	76,889	76,660
Basic and diluted loss per share	$ 0.18	$ (0.13)	$ (0.89)	$ (1.49)	$ 0.23	$ (0.02)	$ (0.40)	$ (0.71)	$ (2.32)	$ (0.90)	$ (1.33)