Revenues - Contract Asset and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Revenue Recognition [Abstract]
Short-term unbilled receivables, net	$ 10,048	$ 11,707
Long-term unbilled receivables, net	14,338	12,260
Total contract assets	24,386	23,967
Short-term deferred revenues, net	108,602	90,894
Long-term deferred revenues	6,019	7,083
Total contract liabilities	$ 114,621	$ 97,977