| Cover | Aug. 02, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Amendment Description | This Amendment No. 2 to Current Report on Form 8-K/A (this "Second Amendment") is being filed by Stagwell Inc., a Delaware Corporation (the "Company"), to amend its Current Report on Form 8-K filed with the U.S. Securities and Exchange Commission (the "SEC") on August 2, 2021 (as amended by Amendment No. 1 to Current Report on Form 8-K/A of the Company filed with the SEC on September 16, 2021, the "Original 8-K"), in connection with the consummation on August 2, 2021 of the transactions contemplated by that certain Transaction Agreement, dated as of December 21, 2020, as amended on June 4, 2021 and July 8, 2021 (the "Transaction Agreement"), by and among certain subsidiaries of Stagwell Media LP, MDC Partners Inc., New MDC LLC and Midas Merger Sub 1 LLC (the transactions contemplated by the Transaction Agreement, the "Transactions"). |
| Document Period End Date | Aug. 2, 2021 |
| Entity File Number | 001-13718 |
| Entity Registrant Name | STAGWELL INC. |
| Entity Central Index Key | 0000876883 |
| Entity Tax Identification Number | 86-1390679 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | One World Trade Center |
| Entity Address, Address Line Two | Floor 65 |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10007 |
| City Area Code | 646 |
| Local Phone Number | 429-1800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock, $0.001 par value |
| Trading Symbol | STGW |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
