Acquisitions and Dispositions - Narrative (Details) $ / shares in Units, £ in Thousands, shares in Thousands															3 Months Ended	5 Months Ended	7 Months Ended	8 Months Ended	12 Months Ended
	Oct. 03, 2022 USD ($)	Jul. 15, 2022 USD ($)	Jul. 12, 2022 USD ($)	May 31, 2022 USD ($)	Apr. 19, 2022 USD ($)	Apr. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 01, 2021 USD ($)	Oct. 01, 2021 USD ($)	Aug. 02, 2021 USD ($) $ / shares shares	Oct. 30, 2020 USD ($)	Aug. 14, 2020 USD ($)	Feb. 14, 2020 USD ($)	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2023	Oct. 03, 2022 GBP (£)	Jul. 12, 2022 GBP (£)	Dec. 31, 2021 GBP (£)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Goodwill							$ 1,652,723,000								$ 1,566,956,000	$ 1,652,723,000	$ 1,566,956,000	$ 1,566,956,000	$ 1,566,956,000	$ 1,652,723,000	$ 351,725,000					$ 325,185,000
Revenues																			2,687,792,000	1,469,363,000	888,032,000
Income attributable to noncontrolling interests																			38,573,000	14,884,000	15,105,000
Net Income (Loss) Attributable to Parent																			27,269,000	21,036,000	56,356,000
Net income																			65,842,000	35,920,000	71,461,000
Payments for Acquire Businesses, Working Capital Payments | £								£ 9,000
Income attributable to noncontrolling interests																			$ 38,573,000	14,884,000	$ 15,105,000
Stagwell Media
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash											$ 1.80
MDC
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable											$ 80,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life											13 years
Goodwill							1,299,374,000				$ 1,290,347,000					1,299,374,000				1,299,374,000
Business Acquisition, Share Price | $ / shares											$ 5.42
Revenues																605,448,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net											$ 429,062,000
MDC | Common Class C | Stagwell Media
Business Acquisition [Line Items]
Stock Issued During Period, Shares, Acquisitions | shares											179,970
MDC | Common Units | Stagwell OpCo
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)											69.55%
MDC | Common Class B
Business Acquisition [Line Items]
Common Stock, Par or Stated Value Per Share | $ / shares											$ 0.001
MDC | Integrated Agencies Network
Business Acquisition [Line Items]
Goodwill											$ 932,582,000
MDC | Brand Performance Network
Business Acquisition [Line Items]
Goodwill											285,396,000
MDC | Communications Network
Business Acquisition [Line Items]
Goodwill											$ 72,369,000
Goodstuff Holdings Limited
Business Acquisition [Line Items]
Closing cash payment | £								21,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life											10 years
Goodwill							4,410,000									4,410,000				4,410,000
Payment for contingent consideration | £								8,000
Payments to Acquire Businesses, Deferred Payments | £								4,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net							$ 28,188,000									$ 28,188,000				$ 28,188,000
Payment for contingent consideration | £								8,000
Payments to Acquire Businesses, Deferred Payments | £								£ 4,000
Goodstuff Holdings Limited | Maximum
Business Acquisition [Line Items]
Deferred acquisition consideration | £																									£ 22,000
Targeted Victory
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)										27.00%
Aggregate purchase price										$ 73,898,000
Deferred acquisition consideration										$ 46,618,000
Business Acquisition, Percentage of Voting Interests Acquired, Step One										13.30%
Business Combination, Consideration Transferred, Redeemable Noncontrolling Interest										$ 27,280,000
Business Acquisition, Percentage of Voting Interests Acquired, Step One										13.30%
Business Combination, Consideration Transferred, Redeemable Noncontrolling Interest										$ 27,280,000
Targeted Victory | Forecast
Business Acquisition [Line Items]
Business Acquisitions, Percentage of Voting Interests Acquired, Step Two																						13.30%
Business Acquisitions, Percentage of Voting Interests Acquired, Step Two																						13.30%
Targeted Victory | Common Class A
Business Acquisition [Line Items]
Business Combination, Contingent Consideration Arrangements, Purchase Price Option Sacrificed in Shares, Percentage										50.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High										$ 135,000,000
Business Combination, Contingent Consideration Arrangements, Purchase Price Option Sacrificed in Shares, Percentage										50.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High										$ 135,000,000
Concentric
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)									27.00%
Aggregate purchase price									$ 8,058,000
Closing cash payment									1,581,000
Deferred acquisition consideration									$ 6,477,000
Instrument Holdings Inc.
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)							49.00%									49.00%				49.00%					49.00%
Aggregate purchase price							$ 157,072,000
Closing cash payment							37,500,000
Business Combination, Consideration Transferred, Deferred Acquisition Payment							82,072,000
Business Combination, Consideration Transferred, Deferred Acquisition Payment							82,072,000
Instrument Holdings Inc. | Common Class A
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable							$ 37,500,000
Hello Design
Business Acquisition [Line Items]
Aggregate purchase price						$ 4,600,000
Closing cash payment						3,600,000
Deferred acquisition consideration						$ 1,000,000
BNG
Business Acquisition [Line Items]
Aggregate purchase price					$ 20,695,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					10 years
Goodwill					$ 24,423,000
Estimated contingent consideration					$ 50,000,000
Contingent consideration payable in cash (percent)					67.00%
Contingent consideration payable in equity (percent)					33.00%
Revenues																		20,544,000
Net income																		$ 67,000
TMA Direct
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)				87.00%
Aggregate purchase price				$ 17,247,000
Deferred acquisition consideration				$ 457,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				10 years
Goodwill				$ 6,569,000
Business Acquisition, Percentage of Voting Interests Acquired, Step One				13.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High				$ 13,330,000
Revenues																	7,659,000
Net income																	$ 889,000
Business Acquisition, Percentage of Voting Interests Acquired, Step One				13.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High				$ 13,330,000
Epicenter
Business Acquisition [Line Items]
Closing cash payment	$ 9,864,000
Deferred acquisition consideration	$ 5,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Goodwill	$ 4,416,000
Revenues															1,028,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 11,864,000
Net income															1,183,000
PEP Group
Business Acquisition [Line Items]
Aggregate purchase price			$ 521,000
Estimated contingent consideration | £																								£ 2,553
Apollo
Business Acquisition [Line Items]
Aggregate purchase price		$ 2,300,000
Payments to Acquire Business, First Payment		1,000,000
Payments to Acquire Business, Second Payment		$ 1,500,000
Sloane and Company LLC
Business Acquisition [Line Items]
Aggregate purchase price														$ 24,400,000
Goodwill														16,275,000
Business Combination, Consideration Transferred, Liabilities Incurred														4,800,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net														24,416,000
Sloane and Company LLC | Stagwell Media
Business Acquisition [Line Items]
Closing cash payment														$ 19,600,000
Kettle
Business Acquisition [Line Items]
Aggregate purchase price													$ 5,400,000
Closing cash payment													4,900,000
Deferred acquisition consideration													11,900,000
Goodwill													1,323,000
Business Combination, Consideration Transferred, Liabilities Incurred													500,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net													$ 5,402,000
Truelogic
Business Acquisition [Line Items]
Aggregate purchase price												$ 17,300,000
Closing cash payment												8,900,000
Deferred acquisition consideration												500,000
Goodwill												6,184,000
Business Combination, Consideration Transferred, Liabilities Incurred												7,900,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net												$ 17,300,000
Maru Group
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	8 years
Goodwill	$ 24,204,000
Revenues															8,786,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 25,793,000																						£ 23,000
Net income															2,135,000
Wolfgang
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)	80.00%																						80.00%
Closing cash payment	$ 3,750,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Goodwill	$ 2,451,000
Revenues															2,072,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	6,160,000
Net income															$ 297,000
Wolfgang | Common Class A
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	$ 1,178,000
Shares issued by the Company (shares) | shares															175