Segment Operating Results - Revenues Derived from Clients by Geographical Areas (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net Revenues	$ 447,810	$ 407,084
United States [Member]
Segment Reporting Information [Line Items]
Net Revenues	365,215	274,122
Europe And Other [Member]
Segment Reporting Information [Line Items]
Net Revenues	80,021	129,284
Latin America [Member]
Segment Reporting Information [Line Items]
Net Revenues	$ 2,574	$ 3,678