Intangible Assets and Liabilities Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Intangible assets, Gross	$ 965,586	$ 978,060
Intangible assets, Accumulated (Amortization) Accretion	(763,265)	(723,577)
Intangible assets, Net	202,321	254,483
Intangible assets, Gross	965,586	981,160	$ 996,538	$ 769,851
Intangible assets, Net	202,321	257,583
Intangible liabilities, Gross	(23,900)	(23,900)	$ (23,900)	$ 0
Intangible liabilities, Accumulated (Amortization) Accretion	11,392	5,217
Intangible liabilities, Net	(12,508)	(18,683)
Core-developed technology [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	500,624	507,100
Intangible assets, Accumulated (Amortization) Accretion	(443,313)	(429,955)
Intangible assets, Net	57,311	77,145
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	375,094	379,614
Intangible assets, Accumulated (Amortization) Accretion	(236,824)	(212,538)
Intangible assets, Net	138,270	167,076
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	77,848	78,746
Intangible assets, Accumulated (Amortization) Accretion	(71,803)	(69,879)
Intangible assets, Net	6,045	8,867
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	12,020	12,600
Intangible assets, Accumulated (Amortization) Accretion	(11,325)	(11,205)
Intangible assets, Net	695	1,395
In Process Research and Development [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	0	3,100
Intangible assets, Accumulated (Amortization) Accretion	0	0
Intangible assets, Net	$ 0	$ 3,100