Intangible Assets Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Intangible Assets [Line Items]
Gross Assets	$ 1,025,830	$ 769,851		$ 669,896
Accumulated Amortization	(714,446)	(674,623)
Net Assets	311,384	95,228
Intangible Assets, Net (Excluding Goodwill)	318,984	95,228
Intangible Assets, Gross (Excluding Goodwill)	1,033,430		$ 686,064
Finite-lived intangible liabilities, Gross	(23,900)	0	$ 0	$ 0
Finite-Lived Intangible Liabilities, Accumulated Accretion	1,304	0
Finite-Lived Intangible Liabilities, Net	(22,596)	0
Core-developed technology [Member]
Intangible Assets [Line Items]
Gross Assets	531,263	429,548
Accumulated Amortization	(423,634)	(399,969)
Net Assets	107,629	29,579
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Gross Assets	400,566	258,586
Accumulated Amortization	(210,757)	(197,582)
Net Assets	189,809	61,004
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Gross Assets	82,337	70,056
Accumulated Amortization	(68,982)	(66,004)
Net Assets	13,355	4,052
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Gross Assets	11,664	11,661
Accumulated Amortization	(11,073)	(11,068)
Net Assets	591	593
In Process Research and Development [Member]
Intangible Assets [Line Items]
Gross Assets	7,600	0
Accumulated Amortization	0	0
Net Assets	$ 7,600	$ 0