Revenues, net - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Accounts receivable, including unbilled receivables	$ 158,939		$ 173,027
Less: Allowance for lifetime expected credit loss	(1,434)	$ (1,346)	(1,163)	$ (1,163)	$ (1,168)	$ (1,255)	$ (956)
Accounts receivable, net	$ 157,505		$ 171,864	$ 171,864