Segment Information (Details 1) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) reportable_segment	Jun. 30, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reportable_segment			3
Revenues	$ 672,913	$ 209,560	$ 1,315,816	$ 390,802
Adjusted EBITDA	111,319	38,718	212,731	62,560
Depreciation, Depletion and Amortization, Nonproduction	(32,231)	(10,381)	(63,435)	(21,331)
Asset Impairment Charges	(2,266)	0	(2,823)	0
Stock-based compensation	(13,131)	0	(21,152)	0
Deferred Acquisition Consideration Expense (Income)	(13,472)	(2,098)	(15,369)	(6,034)
Other items, net	(1,887)	(1,808)	(6,960)	(4,749)
Operating income	48,332	24,431	102,992	30,446
Interest and Debt Expense	(18,151)	(1,935)	(36,880)	(3,286)
Foreign exchange, net	70	(385)	(236)	(1,062)
Other Nonoperating Income (Expense)	(121)	(101)	35	1,184
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	30,130	22,010	65,911	27,282
Income tax expense	5,421	3,348	8,610	4,021
Income Loss From Continuing Operations Before Equity In Earnings Of Non-consolidated Affiliates	24,709	18,662	57,301	23,261
Income (Loss) from Equity Method Investments	(190)	(3)	840	1
Net income	24,519	18,659	58,141	23,262
Net Income (Loss) Attributable to Noncontrolling Interest	(14,056)	(1,314)	(35,003)	(1,552)
Net Income (Loss) Attributable to Parent	10,463	17,345	23,138	21,710
Operating Segments | Integrated Agencies Network
Segment Reporting Information [Line Items]
Revenues	378,168	81,639	728,639	150,587
Adjusted EBITDA	70,307	19,755	139,696	34,251
Depreciation, Depletion and Amortization, Nonproduction	18,010	2,691	36,890	5,293
Stock-based compensation	(4,663)	0	(9,736)	0
Operating Segments | Media Network
Segment Reporting Information [Line Items]
Revenues	194,296	70,560	392,083	134,283
Adjusted EBITDA	33,699	9,129	64,947	12,821
Depreciation, Depletion and Amortization, Nonproduction	8,643	5,313	16,839	10,572
Stock-based compensation	(4,969)	0	(6,229)	0
Operating Segments | Communications Network
Segment Reporting Information [Line Items]
Revenues	97,770	47,738	189,305	90,446
Adjusted EBITDA	17,231	9,962	33,168	17,936
Depreciation, Depletion and Amortization, Nonproduction	2,524	1,395	5,064	2,977
Stock-based compensation	(649)	0	(406)	0
Operating Segments | All Other
Segment Reporting Information [Line Items]
Revenues	2,679	9,623	5,789	15,486
Adjusted EBITDA	(485)	298	(609)	(1,313)
Depreciation, Depletion and Amortization, Nonproduction	750	496	1,251	1,518
Stock-based compensation	0	0	(8)	0
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Adjusted EBITDA	(9,433)	(426)	(24,471)	(1,135)
Depreciation, Depletion and Amortization, Nonproduction	2,304	486	3,391	971
Stock-based compensation	$ (2,850)	$ 0	$ (4,773)	$ 0