Segment Information (Narrative) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment									3
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 5,467,434	$ 5,244,905	$ 4,923,116	$ 4,520,992	$ 4,186,841	$ 3,999,374	$ 3,907,270	$ 3,700,856	$ 20,156,447	$ 15,794,341	$ 11,692,713
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 9,500,000	$ 8,000,000	$ 6,600,000