Goodwill and Intangible Assets (Changes in Carrying Amounts of Goodwill) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 1,531,455
Goodwill acquired	81,725
Purchase accounting adjustments	1,636
Foreign exchange translation	(11,476)
Ending balance	1,603,340
Operating Segments | Digital Media
Goodwill [Roll Forward]
Beginning balance	996,659
Goodwill acquired	81,725
Purchase accounting adjustments	1,773
Foreign exchange translation	(2,584)
Ending balance	1,077,573
Operating Segments | Cybersecurity and Martech
Goodwill [Roll Forward]
Beginning balance	534,796
Goodwill acquired	0
Purchase accounting adjustments	(137)
Foreign exchange translation	(8,892)
Ending balance	$ 525,767