v3.26.3
Noncontrolling and Redeemable Noncontrolling Interests - Noncontrolling Interests (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Apr. 04, 2025
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Noncontrolling Interest [Line Items]            
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest   $ (947) $ (248) $ 609 $ (6,259)  
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest   1,224 (608) (673) 3,622 $ (7,246)
Income attributable to noncontrolling interests   277 (856) (1,282) (2,637)  
Common Class C            
Noncontrolling Interest [Line Items]            
Conversion of Stock, Shares Converted 151,648,741          
Stagwell Global            
Noncontrolling Interest [Line Items]            
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest   (947) (248) (609) 378  
Income attributable to noncontrolling interests         4,000  
Stagwell Media            
Noncontrolling Interest [Line Items]            
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest   $ 0 $ 0 $ 0 (6,637)  
Income attributable to noncontrolling interests         $ (6,637)