UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Revenue:
Revenues	$ 742,998	$ 711,281	$ 2,101,556	$ 2,052,508
Operating expenses:
Cost of services	470,937	457,018	1,342,240	1,340,456
Office and general expenses	166,422	176,440	528,845	507,916
Depreciation and amortization	44,260	36,044	127,635	112,881
Impairment and other losses	466	0	466	1,715
Costs and Expenses, Total	682,085	669,502	1,999,186	1,962,968
Operating Income (Loss), Total	60,913	41,779	102,370	89,540
Other income (expense):
Interest expense, net	(25,196)	(23,781)	(72,007)	(68,279)
Foreign exchange, net	(366)	1,312	(484)	(2,301)
Other, net	(2,032)	249	(2,143)	(825)
Nonoperating Income (Expense), Total	(27,594)	(22,220)	(74,634)	(71,405)
Income before income taxes and equity in earnings of non-consolidated affiliates	33,319	19,559	27,736	18,135
Income tax expense	9,555	5,691	13,950	9,441
Income before equity in earnings of non-consolidated affiliates	23,764	13,868	13,786	8,694
Equity in income (loss) of non-consolidated affiliates	(1)	(4)	18	503
Net income	23,763	13,864	13,804	9,197
Net (income) loss attributable to noncontrolling and redeemable noncontrolling interests	856	(10,593)	2,637	(10,173)
Net income (loss) attributable to Stagwell Inc. common shareholders	$ 24,619	$ 3,271	$ 16,441	$ (976)
Earnings Per Share [Abstract]
Earnings per share, basic	$ 0.10	$ 0.03	$ 0.08	$ (0.01)
Earnings per share, diluted	$ 0.09	$ 0.03	$ 0.04	$ (0.01)
Weighted Average Number Of Shares Outstanding For Basic and Diluted [Abstract]
Weighted Average Number of Shares Outstanding, Basic	255,952	108,198	210,139	111,436
Weighted Average Number of Shares Outstanding, Diluted	259,583	112,190	266,773	111,436