Segment Information (Revenue and Income (Losses) from Operations for Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2012	Aug. 31, 2011
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	$ 107,173	$ 124,511	$ 337,158	$ 386,371
Total income (loss) from operations	13,997	14,280	24,132	70,636
Amortization of acquired intangibles	(5,385)	(5,875)	(16,283)	(17,979)
Stock-based compensation	(7,139)	(9,368)	(20,720)	(18,552)
Transition expenses		(196)		(1,054)
Restructuring expenses	(2,787)	(1,369)	(11,175)	(4,627)
Acquisition-related expenses	0	0	(215)	0
Litigation settlement			(900)
Proxy contest-related costs	(21)		(3,259)
Core segment [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	78,317	88,683	243,934	267,160
Total income (loss) from operations	20,461	39,327	84,066	119,192
Non-Core segment [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	28,856	35,828	93,224	119,211
Total income (loss) from operations	$ 8,868	$ (8,239)	$ (7,382)	$ (6,344)