Noncontrolling and Redeemable Noncontrolling Interests - Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest		$ (19,780)	$ 42,142	$ 21,990
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	$ 634	3,005	(634)	8,135
Income attributable to noncontrolling interests		22,785	41,508	30,125
Nonredeemable Noncontrolling Interest		445,174	468,577
Stagwell Global
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest		2,636	3,076	5,986
Income attributable to noncontrolling interests		(5,641)	2,442	14,121
Nonredeemable Noncontrolling Interest		21,746	32,362
Stagwell Media
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest		17,144	39,066	16,004
Income attributable to noncontrolling interests		(17,144)	39,066	$ 16,004
Nonredeemable Noncontrolling Interest		$ 423,428	$ 436,215