Segment Information (Details 1) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) reportable_segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reportable_segment	3
Revenues	$ 2,687,792	$ 1,469,363	$ 888,032
Adjusted EBITDA	451,118	253,652	143,168
Depreciation, Depletion and Amortization, Nonproduction	(131,273)	(77,503)	(41,025)
Asset Impairment Charges	(122,179)	(16,240)	0
Stock-based compensation	(33,152)	(75,032)
Deferred Acquisition Consideration Expense (Income)	13,405	(18,721)	(4,497)
Other items, net	(18,691)	(21,430)	(13,906)
Operating income	159,228	44,726	83,740
Interest and Debt Expense	(76,062)	(31,894)	(6,223)
Foreign exchange, net	(2,606)	(3,332)	(721)
Other Nonoperating Income (Expense)	(7,059)	50,058	544
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	73,501	59,558	77,340
Income tax expense	7,580	23,398	5,937
Income Loss From Continuing Operations Before Equity In Earnings Of Non-consolidated Affiliates	65,921	36,160	71,403
Income (Loss) from Equity Method Investments	(79)	(240)	58
Net income	65,842	35,920	71,461
Net Income (Loss) Attributable to Noncontrolling Interest	(38,573)	(14,884)	(15,105)
Net Income (Loss) Attributable to Parent	27,269	21,036	56,356
Severance Costs	10,600
Operating Segments | Integrated Agencies Network
Segment Reporting Information [Line Items]
Revenues	1,479,802	770,056	221,595
Adjusted EBITDA	293,643	163,596	42,332
Depreciation, Depletion and Amortization, Nonproduction	74,609	37,646	9,360
Stock-based compensation	(13,774)	(47,190)
Operating Segments | Brand Performance Network
Segment Reporting Information [Line Items]
Revenues	757,208	424,632	262,362
Adjusted EBITDA	115,835	65,942	27,697
Depreciation, Depletion and Amortization, Nonproduction	33,674	26,031	20,117
Stock-based compensation	(5,830)	(5,251)
Operating Segments | Communications Network
Segment Reporting Information [Line Items]
Revenues	430,820	248,832	382,815
Adjusted EBITDA	85,684	45,527	78,562
Depreciation, Depletion and Amortization, Nonproduction	10,831	7,553	5,903
Stock-based compensation	(1,797)	(15,928)
Operating Segments | All Other
Segment Reporting Information [Line Items]
Revenues	19,962	25,843	21,260
Adjusted EBITDA	(933)	(769)	(1,893)
Depreciation, Depletion and Amortization, Nonproduction	5,234	2,498	3,681
Stock-based compensation	(41)	(39)
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Adjusted EBITDA	(43,111)	(20,644)	(3,530)
Depreciation, Depletion and Amortization, Nonproduction	6,925	3,775	$ 1,964
Stock-based compensation	$ (11,710)	$ (6,624)