Intangible Assets (Intangible Assets Other Than Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 255,671	$ 254,288
Intangible assets with finite lives: Accumulated Amortization	(207,333)	(186,013)
Intangible assets with finite lives: Net	$ 48,338	68,275
Weighted average useful life remaining (in years)	5 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 103,661	103,332
Intangible assets with finite lives: Accumulated Amortization	(77,021)	(67,129)
Intangible assets with finite lives: Net	$ 26,640	36,203
Weighted average useful life remaining (in years)	4 years
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 54,378	52,691
Intangible assets with finite lives: Accumulated Amortization	(51,875)	(47,546)
Intangible assets with finite lives: Net	$ 2,503	5,145
Weighted average useful life remaining (in years)	1 year
Trade names
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 23,907	25,096
Intangible assets with finite lives: Accumulated Amortization	(19,133)	(17,669)
Intangible assets with finite lives: Net	$ 4,774	7,427
Weighted average useful life remaining (in years)	4 years
Patent costs
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 11,760	11,032
Intangible assets with finite lives: Accumulated Amortization	(9,535)	(8,382)
Intangible assets with finite lives: Net	$ 2,225	2,650
Weighted average useful life remaining (in years)	15 years
Trade secrets
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 19,494	19,374
Intangible assets with finite lives: Accumulated Amortization	(15,714)	(13,574)
Intangible assets with finite lives: Net	$ 3,780	5,800
Weighted average useful life remaining (in years)	2 years
Acquired patents
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 16,215	16,212
Intangible assets with finite lives: Accumulated Amortization	(14,706)	(13,160)
Intangible assets with finite lives: Net	$ 1,509	3,052
Weighted average useful life remaining (in years)	7 years
Other
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 26,256	26,551
Intangible assets with finite lives: Accumulated Amortization	(19,349)	(18,553)
Intangible assets with finite lives: Net	$ 6,907	$ 7,998
Weighted average useful life remaining (in years)	1 year