Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 651,740	$ 670,059
United States
Disaggregation of Revenue [Line Items]
Revenues	512,542	563,548
Other
Disaggregation of Revenue [Line Items]
Revenues	101,314	68,750
UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Revenues	37,884	37,761
Digital Transformation
Disaggregation of Revenue [Line Items]
Revenues	116,466	115,759
Creativity and Communications
Disaggregation of Revenue [Line Items]
Revenues	303,034	291,653
Performance Media and Data
Disaggregation of Revenue [Line Items]
Revenues	109,817	157,020
Consumer Insights and Strategy
Disaggregation of Revenue [Line Items]
Revenues	48,891	45,769
Stagwell Marketing Cloud Group
Disaggregation of Revenue [Line Items]
Revenues	$ 73,532	$ 59,858