Intangible Assets Gross Carrying Amount and Accumulated Amortization (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Gross Assets	$ 765,712	$ 749,194	$ 806,535	$ 759,152
Accumulated Amortization	(531,399)	(509,694)
Net	234,313	239,500
Core Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Assets	394,375	387,606
Accumulated Amortization	(316,213)	(305,285)
Net	78,162	82,321
Customer Contracts And Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Assets	286,978	278,581
Accumulated Amortization	(140,418)	(131,418)
Net	146,560	147,163
Trade Marks And Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Assets	73,264	71,854
Accumulated Amortization	(63,877)	(62,206)
Net	9,387	9,648
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Assets	11,095	11,153
Accumulated Amortization	(10,891)	(10,785)
Net	$ 204	$ 368