Segment Information - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Revenues	$ 860,063	$ 840,748	$ 1,549,309	$ 1,549,120
Operating Segments
Segment Reporting Information [Line Items]
Revenues	962,266	954,120	1,742,392	1,754,131
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	481,759	487,444	896,707	903,321
Operating Segments | International
Segment Reporting Information [Line Items]
Revenues	480,507	466,676	845,685	850,810
Operating Segments | International | EMEA
Segment Reporting Information [Line Items]
Revenues	234,107	219,525	450,456	449,069
Operating Segments | International | Latin America
Segment Reporting Information [Line Items]
Revenues	141,310	138,550	216,560	213,018
Operating Segments | International | Asia Pacific
Segment Reporting Information [Line Items]
Revenues	105,090	108,601	178,669	188,723
Sales Adjustments
Segment Reporting Information [Line Items]
Revenues	$ (102,203)	$ (113,372)	$ (193,083)	$ (205,011)