Revenues - Contract Asset and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Revenue Recognition [Abstract]
Short-term unbilled receivables, net	$ 9,602	$ 11,707
Long-term unbilled receivables, net	16,132	12,260
Total contract assets	25,734	23,967
Short-term deferred revenues, net	107,940	90,894
Long-term deferred revenues	6,101	7,083
Total contract liabilities	$ 114,041	$ 97,977