Intangible Assets and Liabilities Gross Carrying Amount and Accumulated Amortization (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Intangible Assets [Line Items]
Intangible assets, Gross	$ 986,107	$ 769,851
Intangible assets, Accumulated (Amortization) Accretion	(695,729)	(674,623)
Intangible assets, Net	290,378	95,228
Intangible assets, Gross	992,507	769,851	$ 747,214	$ 669,896
Intangible assets, Net	296,778	95,228
Intangible liabilities, Gross	(23,900)	0	$ 0	$ 0
Intangible liabilities, Accumulated (Amortization) Accretion	2,609	0
Intangible liabilities, Net	(21,291)	0
Core-developed technology [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	509,896	429,548
Intangible assets, Accumulated (Amortization) Accretion	(413,007)	(399,969)
Intangible assets, Net	96,889	29,579
Customer contracts and relationships [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	384,041	258,586
Intangible assets, Accumulated (Amortization) Accretion	(203,890)	(197,582)
Intangible assets, Net	180,151	61,004
Trademarks and trade names [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	79,569	70,056
Intangible assets, Accumulated (Amortization) Accretion	(67,709)	(66,004)
Intangible assets, Net	11,860	4,052
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	12,601	11,661
Intangible assets, Accumulated (Amortization) Accretion	(11,123)	(11,068)
Intangible assets, Net	1,478	593
In Process Research and Development [Member]
Intangible Assets [Line Items]
Intangible assets, Gross	6,400	0
Intangible assets, Accumulated (Amortization) Accretion	0	0
Intangible assets, Net	$ 6,400	$ 0