Intangible Assets and Liabilities Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Intangible assets, Gross	$ 985,509	$ 978,060
Intangible assets, Accumulated (Amortization) Accretion	(763,742)	(723,577)
Intangible assets, Net	221,767	254,483
Intangible assets, Gross	985,509	981,160	$ 992,507	$ 769,851
Intangible assets, Net	221,767	257,583
Intangible liabilities, Gross	(23,900)	(23,900)	$ (23,900)	$ 0
Intangible liabilities, Accumulated (Amortization) Accretion	9,333	5,217
Intangible liabilities, Net	(14,567)	(18,683)
Core-developed technology [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	511,967	507,100
Intangible assets, Accumulated (Amortization) Accretion	(446,653)	(429,955)
Intangible assets, Net	65,314	77,145
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	382,397	379,614
Intangible assets, Accumulated (Amortization) Accretion	(233,664)	(212,538)
Intangible assets, Net	148,733	167,076
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	79,123	78,746
Intangible assets, Accumulated (Amortization) Accretion	(72,138)	(69,879)
Intangible assets, Net	6,985	8,867
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	12,022	12,600
Intangible assets, Accumulated (Amortization) Accretion	(11,287)	(11,205)
Intangible assets, Net	735	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