Intangible Assets (Intangible Assets Other Than Goodwill) (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 251,363	$ 260,047
Intangible assets with finite lives: Accumulated Amortization	(176,904)	(161,264)
Intangible assets with finite lives: Net	$ 74,459	98,783
Weighted average useful life remaining (in years)	6 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 103,833	105,505
Intangible assets with finite lives: Accumulated Amortization	(64,853)	(57,796)
Intangible assets with finite lives: Net	$ 38,980	47,709
Weighted average useful life remaining (in years)	6 years
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 49,032	54,716
Intangible assets with finite lives: Accumulated Amortization	(42,677)	(39,644)
Intangible assets with finite lives: Net	$ 6,355	15,072
Weighted average useful life remaining (in years)	2 years
Trade names
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 25,200	25,813
Intangible assets with finite lives: Accumulated Amortization	(17,111)	(15,552)
Intangible assets with finite lives: Net	$ 8,089	10,261
Weighted average useful life remaining (in years)	6 years
Patent costs
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 18,061	17,909
Intangible assets with finite lives: Accumulated Amortization	(8,086)	(7,338)
Intangible assets with finite lives: Net	$ 9,975	10,571
Weighted average useful life remaining (in years)	15 years
Trade secrets
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 19,393	19,431
Intangible assets with finite lives: Accumulated Amortization	(13,066)	(11,530)
Intangible assets with finite lives: Net	$ 6,327	7,901
Weighted average useful life remaining (in years)	4 years
Acquired patents
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 16,220	16,661
Intangible assets with finite lives: Accumulated Amortization	(12,761)	(11,969)
Intangible assets with finite lives: Net	$ 3,459	4,692
Weighted average useful life remaining (in years)	8 years
Other
Finite-Lived Intangible Assets [Line Items]
Intangible assets with finite lives: Gross	$ 19,624	20,012
Intangible assets with finite lives: Accumulated Amortization	(18,350)	(17,435)
Intangible assets with finite lives: Net	$ 1,274	$ 2,577
Weighted average useful life remaining (in years)	2 years

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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