Intangible Assets Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 702,507				$ 748,148
Accumulated Amortization	(600,575)				(608,239)
Intangible assets, net	101,932	$ 111,767	$ 117,136	$ 122,431	139,909	$ 155,432	$ 172,927	$ 184,052
Net	101,932				139,909
Intangible Assets, Gross (Excluding Goodwill)	702,507				748,148				$ 804,281
Core-developed technology [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	388,981				405,434
Accumulated Amortization	(358,092)				(359,500)
Net	30,889				45,934
Customer contracts and relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	238,379				262,930
Accumulated Amortization	(168,885)				(172,755)
Net	69,494				90,175
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	64,069				68,205
Accumulated Amortization	(62,571)				(64,905)
Net	1,498				3,300
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	11,078				11,579
Accumulated Amortization	(11,027)				(11,079)
Net	$ 51				$ 500