Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Movement in Deferred Revenue [Roll Forward]
Beginning balance	$ 343,174	$ 299,730
Acquired deferred revenue	6,880	2,470
Deferral of revenue	1,532,549	1,339,964
Recognition of deferred revenue	(1,515,892)	(1,293,636)
Currency translation	(1,437)	(5,354)
Ending balance	$ 365,274	$ 343,174