UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current Assets
Cash and cash equivalents	$ 165,251	$ 184,009
Accounts receivable, net	725,346	696,937
Expenditures billable to clients	57,873	63,065
Other current assets	71,249	61,830
Total Current Assets	1,019,719	1,005,841
Fixed assets, net	123,128	118,603
Right-of-use lease assets - operating leases	283,974	311,654
Goodwill	1,615,694	1,652,723
Other intangible assets, net	879,049	937,695
Other assets	47,784	29,064
Total Assets	3,969,348	4,055,580
Current Liabilities
Accounts payable	294,402	271,769
Accrued media	188,344	237,794
Accruals and other liabilities	211,263	272,533
Advance billings	340,675	361,885
Current portion of lease liabilities - operating leases	73,659	72,255
Current portion of deferred acquisition consideration	74,426	77,946
Total Current Liabilities	1,182,769	1,294,182
Long-term debt	1,329,134	1,191,601
Long-term portion of deferred acquisition consideration	85,163	144,423
Long-term lease liabilities - operating leases	308,162	342,730
Deferred tax liabilities, net	103,243	103,093
Other liabilities	70,167	57,147
Total Liabilities	3,078,638	3,133,176
Redeemable Noncontrolling Interests	65,817	43,364
Commitments and Contingencies
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Common Stock, Value, Issued	348,663	382,893
Retained Earnings (Accumulated Deficit)	6,573	(6,982)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(64,956)	(5,278)
Stockholders' Equity Attributable to Parent, Total	290,417	370,753
Stockholders' Equity Attributable to Noncontrolling Interest	534,476	508,287
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Total	824,893	879,040
Liabilities and Equity, Total	3,969,348	4,055,580
Common Class A and Common Class B
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Common shares	135	118
Common Class C
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Common shares	$ 2	$ 2