Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Short-term unbilled receivables	$ 13,895	$ 11,707
Long-term unbilled receivables	17,205	12,260
Total contract assets	31,100	23,967
Short-term deferred revenues, net	100,053	90,894
Long-term deferred revenues	5,673	7,083
Total contract liabilities	$ 105,726	$ 97,977