Segment Information - Reconciliation of Segment Gross Contribution to Net Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Costs and expenses:
Cost of services and product development	$ 1,444,093	$ 1,345,024	$ 1,550,568
Selling, general and administrative	2,155,658	2,038,963	2,103,424
Acquisition and integration charges	6,055	6,282	9,463
Operating income	915,751	490,150	370,087
Interest expense and other, net	(98,191)	(119,203)	(92,273)
Gain on event cancellation insurance claims	152,310	0	0
Loss from divested operations	0	0	(2,075)
Loss on extinguishment of debt	0	(44,814)	0
Provision for income taxes	176,310	59,388	42,449
Net income	$ 793,560	266,745	233,290
Maximum
Costs and expenses:
Percent of target bonus charges allocated to segments	100.00%
Operating Segments
Costs and expenses:
Operating income	$ 3,329,516	2,770,898	2,711,927
Corporate and Reconciling Items
Costs and expenses:
Cost of services and product development	39,647	16,519	17,174
Selling, general and administrative	2,155,658	2,038,963	2,103,424
Depreciation and amortization	212,405	218,984	211,779
Acquisition and integration charges	6,055	6,282	9,463
Operating income	$ (2,413,765)	$ (2,280,748)	$ (2,341,840)