Segment Operating Results - Revenues Derived from Clients by Geographical Areas (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net Revenues	$ 497,073	$ 521,569	$ 944,883	$ 928,653
United States [Member]
Segment Reporting Information [Line Items]
Net Revenues	391,762	386,545	756,977	660,667
Europe And Other [Member]
Segment Reporting Information [Line Items]
Net Revenues	100,224	130,144	180,245	259,428
Latin America [Member]
Segment Reporting Information [Line Items]
Net Revenues	$ 5,087	$ 4,880	$ 7,661	$ 8,558