Revenues - Contract Asset and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Revenue Recognition [Abstract]
Short-term unbilled receivables, net	$ 8,344	$ 11,707
Long-term unbilled receivables, net	15,379	12,260
Total contract assets	23,723	23,967
Short-term deferred revenues, net	101,641	90,894
Long-term deferred revenues	5,163	7,083
Total contract liabilities	$ 106,804	$ 97,977