Comprehensive Income (Loss) (Details) (USD $)	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2009
Comprehensive Income (Loss) [Abstract]
Cumulative translation adjustment, net of tax	$ (21,057,000)	$ (22,066,000)	$ (16,386,000)
Unrealized gain (loss) on available-for-sale securities	25,000	(10,000)	(27,000)
Total accumulated other comprehensive loss	(21,032,000)	(22,076,000)	(16,413,000)
Cumulative translation adjustment, tax effects	$ 10,100,000	$ 10,400,000	$ 7,600,000