Acquisitions - Assets acquired and liabilities assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 7,046,241	$ 6,919,109	$ 6,787,635
Series of individually immaterial business acquisitions
Business Acquisition [Line Items]
Current assets	9,134	23,607	6,713
Property and equipment	9,277	37,457	4,842
Customer relationships	17,200	34,625	0
Noncompetition agreements and other long-term assets	9,964	10,168	1,980
Indefinite-lived licenses	11,432	22,136	31,858
Goodwill	173,244	130,057	90,226
Deferred income taxes	0	(3,962)	0
Liabilities Assumed	(14,200)	(34,068)	(7,159)
Noncontrolling interests assumed	(3,921)	(1,729)	(1,762)
Aggregate purchase price	$ 212,130	$ 218,291	$ 126,698