Segment and Geographic Information Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues from External Customers and Long-Lived Assets
Revenues	$ 3,000,935	$ 3,100,303
UNITED STATES
Revenues from External Customers and Long-Lived Assets
Revenues	1,533,945	1,542,026
UNITED KINGDOM
Revenues from External Customers and Long-Lived Assets
Revenues	390,619	412,813
GERMANY
Revenues from External Customers and Long-Lived Assets
Revenues	374,552	386,465
Other countries
Revenues from External Customers and Long-Lived Assets
Revenues	$ 701,819	$ 758,999