Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Goodwill, Impairment Loss		$ 116,714
Impairment and other losses	$ 11,395	122,179	$ 16,240
Goodwill, Impaired, Accumulated Impairment Loss		116,700
Amortization of Intangible Assets	$ 112,200	$ 103,100	61,100
Weighted Average
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	12 years
Integrated Agencies Network and Brand Performance Network
Finite-Lived Intangible Assets [Line Items]
Impairment and other losses			$ 16,200
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	13 years
Trademarks
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	12 years
Software and Software Development Costs
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	6 years