Intangible Assets Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Intangible Assets [Line Items]
Gross Assets	$ 686,064	$ 669,896	$ 708,981	$ 702,507
Accumulated Amortization	(616,579)	(597,745)
Total intangible assets subject to amortization	69,485	72,151
Core-developed technology [Member]
Intangible Assets [Line Items]
Gross Assets	381,788	372,568
Accumulated Amortization	(365,766)	(354,878)
Total intangible assets subject to amortization	16,022	17,690
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Gross Assets	230,382	224,467
Accumulated Amortization	(176,960)	(170,056)
Total intangible assets subject to amortization	53,422	54,411
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Gross Assets	62,817	61,785
Accumulated Amortization	(62,802)	(61,766)
Total intangible assets subject to amortization	15	19
Other [Member]
Intangible Assets [Line Items]
Gross Assets	11,077	11,076
Accumulated Amortization	(11,051)	(11,045)
Total intangible assets subject to amortization	$ 26	$ 31