Segment Information - Revenue and Long-Lived Assets by Geography (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 segments	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of Reportable Segments									4
Revenue	$ 1,977,947	$ 2,009,575	$ 1,962,636	$ 1,802,570	$ 1,785,922	$ 1,850,653	$ 1,836,981	$ 1,681,540	$ 7,752,728	$ 7,155,096	$ 6,626,648
Property, Plant and Equipment, Net	837,069				787,849				837,069	787,849
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									4,617,813	4,202,434	3,977,925
Property, Plant and Equipment, Net	599,688				528,001				599,688	528,001
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,251,625	1,112,279	1,082,210
Property, Plant and Equipment, Net	136,599				153,564				136,599	153,564
Other Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									794,966	803,741	744,192
Property, Plant and Equipment, Net	39,971				47,374				39,971	47,374
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									686,511	607,873	574,140
Property, Plant and Equipment, Net	42,775				43,516				42,775	43,516
Other Geographical Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									401,813	428,769	248,181
Property, Plant and Equipment, Net	$ 18,036				$ 15,394				$ 18,036	$ 15,394