Acquisitions and Dispositiions - Assets Acquired and Liabilities Assumed - TokBox (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Aug. 01, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 602,970	$ 598,499		$ 373,764
TokBox
Business Acquisition [Line Items]
Cash and cash equivalents			$ 557
Current assets			2,205
Property and equipment			124
Intangible assets			15,602
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets			92
Restricted cash			50
Total assets acquired			18,630
Accounts payable			371
Accrued expenses			6,003
Total liabilities assumed			6,374
Net identifiable assets acquired			12,256
Goodwill			20,650
Total purchase price			$ 32,906