Acquisitions - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Apr. 15, 2019	Feb. 08, 2018	Jun. 30, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill			$ 1,607,848	$ 1,557,653
Opterna International Corp.
Business Acquisition [Line Items]
Total intangible assets subject to amortization	$ 26,900
Goodwill	44,973
Total intangible assets	$ 71,873
Amortization Period	13 years
Opterna International Corp. | Goodwill
Business Acquisition [Line Items]
Goodwill	$ 44,973
Opterna International Corp. | Developed technologies
Business Acquisition [Line Items]
Total intangible assets subject to amortization	$ 3,500
Amortization Period	5 years
Opterna International Corp. | Customer relationships
Business Acquisition [Line Items]
Total intangible assets subject to amortization	$ 22,000
Amortization Period	15 years
Opterna International Corp. | Sales backlog
Business Acquisition [Line Items]
Total intangible assets subject to amortization	$ 900
Amortization Period	15 days
Opterna International Corp. | Trademarks
Business Acquisition [Line Items]
Total intangible assets subject to amortization	$ 500
Amortization Period	2 years
Snell Advanced Media
Business Acquisition [Line Items]
Total intangible assets subject to amortization		$ 51,000
Goodwill		103,466
Total intangible assets		$ 154,466
Amortization Period		6 years 2 months 12 days
Snell Advanced Media | Goodwill
Business Acquisition [Line Items]
Goodwill		$ 103,466
Snell Advanced Media | Developed technologies
Business Acquisition [Line Items]
Total intangible assets subject to amortization		$ 36,500
Amortization Period		5 years
Snell Advanced Media | Customer relationships
Business Acquisition [Line Items]
Total intangible assets subject to amortization		$ 11,000
Amortization Period		12 years
Snell Advanced Media | Sales backlog
Business Acquisition [Line Items]
Total intangible assets subject to amortization		$ 1,900
Amortization Period		9 days
Snell Advanced Media | Trademarks
Business Acquisition [Line Items]
Total intangible assets subject to amortization		$ 1,600
Amortization Period		27 days