Acquisitions (Details) - USD ($)	Apr. 12, 2017	Apr. 04, 2017	Jul. 02, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Equity			$ 1,051,976,000	$ 962,599,000
ViDi Systems S.A.
Business Acquisition [Line Items]
Total purchase price		$ 23,015,000
Cash payment		20,019,000
Holdback to secure potential claims under agreement		$ 2,996,000
Holdback limitation period		18 months
tax deductible goodwill		$ 5,112,000
ViDi Systems S.A. | Completed technologies
Business Acquisition [Line Items]
Amortization period		6 years
ViDi Systems S.A. | Non-compete agreement
Business Acquisition [Line Items]
Amortization period		3 years
GVi Ventures, Inc.
Business Acquisition [Line Items]
Total purchase price	$ 5,368,000
Cash payment	4,069,000
Contingent consideration liabilities	1,299,000		1,299,000
Contingent consideration, low range	0
Contingent consideration, high range	$ 3,500,000
Contingent consideration, period of recognition (in years)	5 years
Contingent consideration, current			274,000
Contingent consideration, noncurrent			$ 1,025,000
GVi Ventures, Inc. | Completed technologies
Business Acquisition [Line Items]
Amortization period	5 years
GVi Ventures, Inc. | Customer relationships
Business Acquisition [Line Items]
Amortization period	8 years