Segment Information (Details 1) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) reporting_segment	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reporting_segment	3
Revenues	$ 1,469,363	$ 888,032
Adjusted EBITDA	253,652	143,168
Depreciation and amortization	(77,503)	(41,025)
Impairment and other losses	(16,240)	0
Stock-based compensation	(75,032)	0
Deferred acquisition consideration	(18,721)	(4,497)
Other items, net	(21,430)	(13,906)
Total Operating Income	44,726	83,740
Interest expense, net	(31,894)	(6,223)
Foreign exchange, net	(3,332)	(721)
Gain on sale of business and other, net	50,058	544
Income tax expense	23,398	5,937
Income before equity in earnings of non-consolidated affiliates	36,160	71,403
Equity in (income) losses of non-consolidated affiliates	(240)	58
Net income (loss) attributable to Stagwell Inc.:	21,036	56,356
Net income	35,920	71,461
Net income attributable to noncontrolling and redeemable noncontrolling interests	(14,884)	(15,105)
Operating Segments | Integrated Agencies Network
Segment Reporting Information [Line Items]
Revenues	819,758	229,646
Adjusted EBITDA	166,768	42,360
Depreciation and amortization	(40,087)	(9,616)
Stock-based compensation	(47,584)	0
Operating Segments | Media Network
Segment Reporting Information [Line Items]
Revenues	374,930	254,311
Adjusted EBITDA	62,770	27,669
Depreciation and amortization	(23,590)	(19,861)
Stock-based compensation	(4,857)	0
Operating Segments | Communications Network
Segment Reporting Information [Line Items]
Revenues	248,832	382,815
Adjusted EBITDA	45,527	78,562
Depreciation and amortization	(7,553)	(5,903)
Stock-based compensation	(15,928)	0
Operating Segments | All Other
Segment Reporting Information [Line Items]
Revenues	25,843	21,260
Adjusted EBITDA	(769)	(1,893)
Depreciation and amortization	(2,498)	(3,681)
Stock-based compensation	(39)	0
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Adjusted EBITDA	(20,644)	(3,530)
Depreciation and amortization	(3,775)	(1,964)
Stock-based compensation	$ (6,624)	$ 0