| Cover Page - USD ($) $ in Billions | 12 Months Ended | | |
| Dec. 31, 2022 | Feb. 24, 2023 | Jun. 30, 2022 |
| Document Information [Line Items] | | | |
| Document Type | 10-K/A | | |
| Document Annual Report | true | | |
| Document Period End Date | Dec. 31, 2022 | | |
| Current Fiscal Year End Date | --12-31 | | |
| Document Transition Report | false | | |
| Entity File Number | 001-37534 | | |
| Entity Registrant Name | PLANET FITNESS, INC. | | |
| Entity Incorporation, State or Country Code | DE | | |
| Entity Tax Identification Number | 38-3942097 | | |
| Entity Address, Address Line One | 4 Liberty Lane West | | |
| Entity Address, City or Town | Hampton | | |
| Entity Address, State or Province | NH | | |
| Entity Address, Postal Zip Code | 03842 | | |
| City Area Code | 603 | | |
| Local Phone Number | 750-0001 | | |
| Title of 12(b) Security | Class A common stock, $0.0001 Par Value | | |
| Trading Symbol | PLNT | | |
| Security Exchange Name | NYSE | | |
| Entity Well-known Seasoned Issuer | Yes | | |
| Entity Voluntary Filers | No | | |
| Entity Current Reporting Status | Yes | | |
| Entity Interactive Data Current | Yes | | |
| Entity Filer Category | Large Accelerated Filer | | |
| Entity Small Business | false | | |
| Entity Emerging Growth Company | false | | |
| ICFR Auditor Attestation Flag | true | | |
| Entity Shell Company | false | | |
| Entity Public Float | | | $ 5.7 |
| Documents Incorporated by Reference | Portions of the Definitive Proxy Statement for the registrant’s 2022 Annual Meeting of Stockholders to be held May 1, 2023, are incorporated by reference into Part III, Items 10-14 of this Annual Report on Form 10-K. | | |
| Amendment Description | This Amendment No. 1 to the Annual Report on Form 10-K/A (this “Amendment”) amends the Annual Report on Form 10-K for the year ended December 31, 2022 (the “Original Report”) of Planet Fitness, Inc. (the “Company”), which was filed with the Securities and Exchange Commission (“SEC”) on March 1, 2023. This Amendment is being filed solely to amend the signature page to provide a conformed signature for the Company, which was inadvertently omitted from the Original Report. The original signature page was fully executed on March 1, 2023 and was in the Company’s possession at the time of the filing of the Original Report.In addition, this Amendment includes an updated exhibit index to include certifications under Section 302 of the Sarbanes-Oxley Act of 2002. Except as described above, this Amendment does not update or modify any other information presented in the Original Report and does not reflect events occurring after the Original Report’s filing date of March 1, 2023. | | |
| Amendment Flag | true | | |
| Document Fiscal Year Focus | 2022 | | |
| Document Fiscal Period Focus | FY | | |
| Entity Central Index Key | 0001637207 | | |
| Common Class A | | | |
| Document Information [Line Items] | | | |
| Entity Common Stock, Shares Outstanding | | 84,857,051 | |
| Common Class B | | | |
| Document Information [Line Items] | | | |
| Entity Common Stock, Shares Outstanding | | 4,586,140 | |
