Goodwill And Acquired Intangible Assets (Carrying Values Of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2012	Nov. 30, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	$ 304,368	$ 302,404
Intangible assets subject to amortization, Accumulated Amortization	(216,341)	(206,846)
Intangible assets subject to amortization, Net Carrying Amount	88,027	95,558
In-process research and development	1,700	1,700
Total intangible assets, Gross Carrying Amount	306,068	304,104
Total intangible assets, Net Carrying Amount	89,727	97,258
Developed Technologies [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	147,224	146,289
Intangible assets subject to amortization, Accumulated Amortization	(105,980)	(102,034)
Intangible assets subject to amortization, Net Carrying Amount	41,244	44,255
Customer Base [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	56,507	56,165
Intangible assets subject to amortization, Accumulated Amortization	(39,030)	(37,376)
Intangible assets subject to amortization, Net Carrying Amount	17,477	18,789
Patents/Core Technologies [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	28,156	27,922
Intangible assets subject to amortization, Accumulated Amortization	(22,531)	(21,542)
Intangible assets subject to amortization, Net Carrying Amount	5,625	6,380
Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	9,835	9,771
Intangible assets subject to amortization, Accumulated Amortization	(7,385)	(7,077)
Intangible assets subject to amortization, Net Carrying Amount	2,450	2,694
Non-Compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	580	580
Intangible assets subject to amortization, Accumulated Amortization	(580)	(580)
Maintenance Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	62,066	61,677
Intangible assets subject to amortization, Accumulated Amortization	(40,835)	(38,237)
Intangible assets subject to amortization, Net Carrying Amount	$ 21,231	$ 23,440