Segment Information - Revenue and Long-Lived Assets by Geography (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segments	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of Reportable Segments | segments									3
Revenue	$ 1,808,950	$ 1,747,403	$ 1,798,094	$ 1,637,671	$ 1,752,530	$ 1,747,775	$ 1,737,371	$ 1,583,210	$ 6,992,118	$ 6,820,886	$ 6,043,224
Property, Plant and Equipment, Net	806,497				787,940				806,497	787,940
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									3,619,717	3,654,102	3,351,466
Property, Plant and Equipment, Net	480,780				459,931				480,780	459,931
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,572,788	1,476,686	1,241,297
Property, Plant and Equipment, Net	239,070				238,986				239,070	238,986
Other Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									631,164	621,831	516,544
Property, Plant and Equipment, Net	59,550				57,016				59,550	57,016
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									867,268	754,845	658,425
Property, Plant and Equipment, Net	24,872				29,074				24,872	29,074
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									301,181	313,422	$ 275,492
Property, Plant and Equipment, Net	$ 2,225				$ 2,933				$ 2,225	$ 2,933