Goodwill And Intangible Assets, Net (Components Of Intangible Assets, Net) (Details) (USD $)	Mar. 31, 2012		Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 406,536,000		$ 402,262,000
Accumulated Amortization and Impairments	(267,269,000)		(251,876,000)
Net	139,267,000		150,386,000
Acquired Technology And IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	247,654,000	[1]	244,680,000	[1]
Accumulated Amortization and Impairments	(165,042,000)	[1]	(157,944,000)	[1]
Net	82,612,000	[1]	86,736,000	[1]
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	124,018,000		122,918,000
Accumulated Amortization and Impairments	(75,126,000)		(67,193,000)
Net	48,892,000		55,725,000
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,268,000		15,068,000
Accumulated Amortization and Impairments	(14,058,000)		(13,896,000)
Net	1,210,000		1,172,000
Trademarks And Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,596,000	[2]	19,596,000	[2]
Accumulated Amortization and Impairments	(13,043,000)	[2]	(12,843,000)	[2]
Net	6,553,000	[2]	6,753,000	[2]
PacketTrap [Member] | Trademarks And Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired indefinite-lived intangible assets	$ 800,000

[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 $0.8 million in trade names related to our acquisition of PacketTrap that have an indefinite useful life, and as such are not being amortized.