Cover

Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2023	Apr. 15, 2024	Jul. 02, 2023
Document Information [Line Items]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-13703
Entity Registrant Name	SIX FLAGS ENTERTAINMENT CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3995059
Entity Address, Address Line One	1000 Ballpark Way, Suite 400
Entity Address, City or Town	Arlington
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	76011
City Area Code	972
Local Phone Number	595-5000
Title of 12(b) Security	Common stock, $0.025 par value per share
Trading Symbol	SIX
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
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	true
Document Financial Statement Restatement Recovery Analysis [Flag]	true
Entity Public Float			$ 1,912.9
Entity Common Stock, Shares Outstanding		84,274,760
Documents Incorporated by Reference [Text Block]	None.
Entity Central Index Key	0000701374
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	true
Amendment Description	EXPLANATORY NOTE On February 29, 2024, Six Flags Entertainment Corporation (the “Company,” “Six Flags,” “we,” or “our”) filed its Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (the “Original Form 10-K”). The Original Form 10-K omitted Part III, Items 10 (Directors, Executive Officers and Corporate Governance), 11 (Executive Compensation), 12 (Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters), 13 (Certain Relationships and Related Transactions and Director Independence) and 14 (Principal Accounting Fees and Services) in reliance on the General Instructions to Form 10-K, which provides that such information may be either incorporated by reference from the registrant’s definitive proxy statement or included in an amendment to Form 10-K, in either case filed with the Securities and Exchange Commission (the “SEC”) not later than 120 days after the end of the fiscal year. We currently do not expect that a definitive proxy statement for a 2024 annual meeting of stockholders will be filed within 120 days after the end of the last fiscal year. Accordingly, this Amendment No. 1 to Form 10-K (this “Amendment”) is being filed solely to: • amend Items 10 through 14 of the Original Form 10-K to include the information required by such Items; and • in accordance with Rule 12b-15 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), file new certifications of the Company’s principal executive officer and principal financial officer required by Rule 13a-14(a) under the Exchange Act as exhibits to this Amendment under Item 15 of Part IV hereof. Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certifications have been omitted. The Company is not including currently dated certifications pursuant to Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. 1350) as no financial statements are being filed with this Amendment. The cover page of the Form 10-K is also amended to delete the reference to incorporation by reference of the Company’s definitive proxy statement. Except as described above, no other changes have been made to the Original Form 10-K. The Original Form 10-K continues to speak as of the date of the Original Form 10-K, and we have not updated the disclosures contained therein to reflect any events which occurred at a date subsequent to the filing of the Original Form 10-K other than as expressly indicated in this Amendment.