Goodwill And Intangible Assets, Net (Components Of Intangible Assets, Net) (Details) (USD $)	Sep. 30, 2011		Dec. 31, 2010
Gross Carrying Amount	$ 328,884,000		$ 266,355,000
Accumulated Amortization	(233,156,000)		(203,570,000)
Net	95,728,000		62,785,000
ScriptLogic [Member] | Trademarks And Trade Names [Member]
Acquired indefinite-lived intangible asset	6,200,000		6,200,000
PacketTrap [Member] | Trademarks And Trade Names [Member]
Acquired indefinite-lived intangible asset	800,000		800,000
Acquired Technology And IPR&D [Member]
Gross Carrying Amount	207,082,000	[1]	164,816,000	[1]
Accumulated Amortization	(150,226,000)	[1]	(133,591,000)	[1]
Net	56,856,000	[1]	31,225,000	[1]
Customer Relationships [Member]
Gross Carrying Amount	91,418,000		74,318,000
Accumulated Amortization	(62,733,000)		(50,639,000)
Net	28,685,000		23,679,000
Non-Compete Agreements [Member]
Gross Carrying Amount	14,689,000		13,919,000
Accumulated Amortization	(13,765,000)		(13,201,000)
Net	924,000		718,000
Trademarks And Trade Names [Member]
Gross Carrying Amount	15,695,000	[2]	13,302,000	[2]
Accumulated Amortization	(6,432,000)	[2]	(6,139,000)	[2]
Net	$ 9,263,000	[2]	$ 7,163,000	[2]

[1] IPR&D projects were identified and valued related to our acquisitions. These projects are continually assessed for impairment. Upon completion, these projects will be amortized over their estimated useful life.

[2] Trademarks and trade names include $6.2 million and $0.8 million in trade names related to our acquisition of ScriptLogic and PacketTrap, respectively, that each have an indefinite useful life, and as such are not being amortized.