Goodwill and Other Intangible Assets - Summary of Changes in Goodwill by Reportable Business Segment (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 4,542,074
Acquisitions	160,257
Acquisition Accounting Adjustments	2,914
Foreign Currency	15,226
Goodwill, ending balance	4,720,471	[1]
North America
Goodwill [Roll Forward]
Goodwill, beginning balance	3,087,875
Acquisitions	141,644
Acquisition Accounting Adjustments	2,914
Foreign Currency	6,130
Goodwill, ending balance	3,238,563
International
Goodwill [Roll Forward]
Goodwill, beginning balance	1,454,199
Acquisitions	18,613
Acquisition Accounting Adjustments	0
Foreign Currency	9,096
Goodwill, ending balance	$ 1,481,908

[1] Reflects the impact of the Company's adoption of ASU 2016-02 "Leases", on January 1, 2019, using a modified retrospective transition method. Under this method, financial results reported in periods prior to 2019 are unchanged. Refer to footnote 2.