Organization and Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 01, 2024	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Nov. 30, 2023	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Other comprehensive income foreign currency translation gain loss after tax			$ (9,412)	$ 9,018	$ (18,896)
Goodwill impairment			$ 233,170		$ 1,367,500
Impairment, Intangible Asset, Indefinite-Lived (Excluding Goodwill), Statement of Income or Comprehensive Income [Extensible Enumeration]			Impairment of Intangible Assets Indefinitelived Including Goodwill	Impairment of Intangible Assets Indefinitelived Including Goodwill	Impairment of Intangible Assets Indefinitelived Including Goodwill
Impairment of long lived assets held for use			$ 0	$ 0	$ 0
Contract with customers liability revenue recognised			$ 19,400	$ 17,600	$ 29,400
Period over which internal use developed software costs are amortised			7 years	7 years	7 years
Unrecognised income tax position		$ 2,858	$ 2,858	$ 2,887	$ 560		$ 563
Effective tax rate recognized		2,200	2,200
Interest and penalties as components of tax expense			1,400	900	200
Unrecognized tax benefits		$ 2,858	$ 2,858	$ 2,887	560		$ 563
Common stock, par value		$ 0.0001	$ 0.0001	$ 0.0001
Proceeds from sale of Equity Method Investments			$ 0	$ 4,428	0
Class of warrant or right exercise price of warrants or rights		$ 0.01	$ 0.01
Common stock, shares issued		320,773,096	320,773,096	322,235,261
Proceeds from Issuance of Common Stock			$ 2,294	$ 2,248	3,320
Gain on Deconsolidation			0	58,891	0
Stock-based compensation expense			31,019	38,933	35,101
Indefinite lived intangible assets (excluding goodwill) fair value disclosure percentage	6.00%
Intangible asset impairment charge				43,500
Deferred tax liabilities		$ 144,152	144,152	$ 201,882
Advantage Smollan Ltd [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Subsidiary, Ownership Percentage, Parent						49.60%
Sales Trade Name [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Impairment of indefinitely lived intangible assets			205,000
Branded Services [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Goodwill impairment			133,500
Intangible asset impairment charge		$ 42,000
Branded Agencies [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Goodwill impairment			$ 99,700
Warrant [Member] | ADV [Member] | ADVWW [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Class of warrant or right exercise price of warrants or rights		$ 11.50	$ 11.50
Class A Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value		$ 0.0001	$ 0.0001
Class A Common Stock | Topco [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, shares issued		320,773,096	320,773,096	322,235,261
UNITED STATES [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Other comprehensive income foreign currency translation gain loss after tax			$ 100	$ 100	$ 7,600
Branded Agencies and Experiential Services [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Carrying value in excess of the fair value in percentage terms goodwill		20.00%	20.00%
Branded Services Branded Agencies And Merchandising [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Carrying value in excess of the fair value in percentage terms goodwill		20.00%	20.00%