Revenue Recognition - Changes in Balance of Deferred Revenues (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Revenue Recognition
Balance	$ 44,189
Increase in deferred revenues	65,026
Revenue recognized during the period that was included in deferred revenues at the beginning of the period	(970)
Revenue recognized from performance obligations satisfied within the same period	(23,209)
Transferred in the sale of business	(5,212)
Balance	$ 79,824