Intangible Assets Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Intangible Assets [Line Items]
Gross Assets	$ 746,504	$ 669,896		$ 702,507
Accumulated Amortization	(643,070)	(597,745)
Intangible Assets, Net (Excluding Goodwill)	104,144	72,151
Net Assets	103,434	72,151
Intangible Assets, Gross (Excluding Goodwill)	747,214		$ 699,995
Core-developed technology [Member]
Intangible Assets [Line Items]
Gross Assets	415,616	372,568
Accumulated Amortization	(382,015)	(354,878)
Net Assets	33,601	17,690
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Gross Assets	250,683	224,467
Accumulated Amortization	(185,659)	(170,056)
Net Assets	65,024	54,411
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Gross Assets	68,626	61,785
Accumulated Amortization	(64,340)	(61,766)
Net Assets	4,286	19
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Gross Assets	11,579	11,076
Accumulated Amortization	(11,056)	(11,045)
Net Assets	523	31
In Process Research and Development [Member]
Intangible Assets [Line Items]
Gross Assets	710	0
Accumulated Amortization	0	0
Net Assets	$ 710	$ 0