Business Acquisitions (Details 1) - USD ($) $ in Thousands	Nov. 30, 2016	Nov. 04, 2016	Jun. 30, 2016	Nov. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 123,100
Finite-lived intangible assets acquired		$ 200
Goodwill				$ 60,494	$ 909,811	$ 801,406	$ 596,316
Point Grey Research, Inc. [Member]
Business Acquisition [Line Items]
Intangible assets acquired		39,800
Goodwill		$ 183,678
Prox Dynamics, AS [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 31,400
Indefinite-lived Intangible Assets Acquired	31400000
Goodwill	$ 96,431
DVTEL [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles					27,400
Indefinite-lived Intangible Assets Acquired				27380
Armasight, Inc. [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets acquired			$ 7,600
Goodwill					$ 32,994
Patents [Member] | Prox Dynamics, AS [Member]
Business Acquisition [Line Items]
Estimated Useful Life	8 years
Indefinite-lived Intangible Assets Acquired	3100
Developed technology | Point Grey Research, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life		10 years
Developed technology | Prox Dynamics, AS [Member]
Business Acquisition [Line Items]
Estimated Useful Life	8 years
Indefinite-lived Intangible Assets Acquired	23400
Trade name | Point Grey Research, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life		7 years
Finite-lived intangible assets acquired		$ 13,200
Trade name | Prox Dynamics, AS [Member]
Business Acquisition [Line Items]
Estimated Useful Life	7 years
Indefinite-lived Intangible Assets Acquired	3500
Trade name | Armasight, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life			4 years
Finite-lived intangible assets acquired			$ 5,200
Trade Names [Member] | Prox Dynamics, AS [Member]
Business Acquisition [Line Items]
Estimated Useful Life	8 years
Indefinite-lived Intangible Assets Acquired	1400
Trade Names [Member] | Armasight, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life			3 years
Finite-lived intangible assets acquired			$ 1,000
Backlog | Point Grey Research, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life		1 year
Finite-lived intangible assets acquired		$ 2,300
Non-Competition Agreements | Point Grey Research, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life		5 years
Finite-lived intangible assets acquired		$ 1,000
Trade Secrets | Armasight, Inc. [Member]
Business Acquisition [Line Items]
Estimated Useful Life			6 years
Finite-lived intangible assets acquired			$ 1,400
Backlog | DVTEL [Member]
Business Acquisition [Line Items]
Weighted average estimated useful life				1 year
Indefinite-lived Intangible Assets Acquired				380
Trade name | DVTEL [Member]
Business Acquisition [Line Items]
Weighted average estimated useful life				10 years
Indefinite-lived Intangible Assets Acquired				3800
Developed technology | Point Grey Research, Inc. [Member]
Business Acquisition [Line Items]
Indefinite-lived intangible assets acquired		$ 23,100
Developed technology | DVTEL [Member]
Business Acquisition [Line Items]
Weighted average estimated useful life				7 years 6 months
Indefinite-lived Intangible Assets Acquired				21500
In-process research and development | DVTEL [Member]
Business Acquisition [Line Items]
Indefinite-lived Intangible Assets Acquired				1700