Goodwill and Intangible Assets (Changes in Carrying Amounts of Goodwill) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 1,546,065
Goodwill acquired	85,900
Goodwill removed due to sale of businesses	(3,983)
Foreign exchange translation	(3,354)
Ending balance	1,624,628
Operating Segments | Digital Media
Goodwill [Roll Forward]
Beginning balance	1,016,880
Goodwill acquired	85,900
Goodwill removed due to sale of businesses	(3,983)
Foreign exchange translation	(1,188)
Ending balance	1,097,609
Operating Segments | Cybersecurity and Martech
Goodwill [Roll Forward]
Beginning balance	529,185
Goodwill acquired	0
Goodwill removed due to sale of businesses	0
Foreign exchange translation	(2,166)
Ending balance	$ 527,019