Acquisitions - ViDi Systems S.A. Purchase Price Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Apr. 04, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 113,208	$ 113,208		$ 95,280
ViDi Systems S.A. [Member]
Business Acquisition [Line Items]
Cash			$ 146
Accounts receivable			425
Prepaid expenses and other current assets			129
Property, plant, and equipment			40
Deferred income tax asset			620
Accounts payable			(98)
Accrued expenses			(716)
Deferred income tax liability			(1,008)
Goodwill			18,333
Purchase price			23,015
Non-compete agreements | ViDi Systems S.A. [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets			370
Technology-Based Intangible Assets [Member] | ViDi Systems S.A. [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets			$ 4,774