Noncontrolling and Redeemable Noncontrolling Interests - Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	7 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2023	Aug. 02, 2021	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest								$ (42,142)	$ 21,990	$ 15,296
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest								634	8,135	(412)
Income attributable to noncontrolling interests	$ 45,073	$ 2,464	$ (1,771)	$ (4,258)	$ (6,029)	$ 39,626	$ (3,565)	41,508	30,125	14,884
Nonredeemable Noncontrolling Interest	468,577							468,577	430,164
Stagwell Global
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest								3,076	5,986	9,170
Income attributable to noncontrolling interests								(2,442)	14,121
Nonredeemable Noncontrolling Interest	32,362							32,362	30,848
Stagwell Media
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest								39,066	16,004	$ 6,126
Income attributable to noncontrolling interests								(39,066)	16,004
Nonredeemable Noncontrolling Interest	$ 436,215							$ 436,215	$ 399,316