Intangible Assets Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Intangible Assets [Line Items]
Gross Assets	$ 708,981	$ 702,507	$ 705,613	$ 748,148
Accumulated Amortization	(612,595)	(600,575)
Net	96,386	101,932
Core-developed technology [Member]
Intangible Assets [Line Items]
Gross Assets	393,957	388,981
Accumulated Amortization	(365,728)	(358,092)
Net	28,229	30,889
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Gross Assets	239,560	238,379
Accumulated Amortization	(172,592)	(168,885)
Net	66,968	69,494
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Gross Assets	64,385	64,069
Accumulated Amortization	(63,243)	(62,571)
Net	1,142	1,498
Other [Member]
Intangible Assets [Line Items]
Gross Assets	11,079	11,078
Accumulated Amortization	(11,032)	(11,027)
Net	$ 47	$ 51