Noncontrolling and Redeemable Noncontrolling Interests - Changes in Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	$ 18,537	$ 1,153
Nonredeemable Noncontrolling Interest	528,365		$ 508,287
Stagwell Global
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	816	1,153
Nonredeemable Noncontrolling Interest	32,970		32,914
Stagwell Media
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	17,721	$ 0
Nonredeemable Noncontrolling Interest	$ 495,395		$ 475,373