v3.25.2
Earnings per Share - Schedule of Share Amounts Used in Calculating Basic and Diluted Earnings Per Common Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 29, 2025
Jun. 30, 2024
Jun. 29, 2025
Jun. 30, 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Net income (loss) attributable to Six Flags Entertainment Corporation $ (99,648) $ 55,553 $ (319,366) $ (77,914)
Basic weighted average common shares outstanding (in shares) 100,652   100,376  
Basic LP Units outstanding (in shares)   50,766   50,717
Diluted weighted average shares of common stock (in shares) 100,652   100,376  
Diluted LP Units outstanding (in shares)   51,395   50,717
Net income (loss) per share of common stock - basic (in dollars per share) $ (0.99)   $ (3.18)  
Net income (loss) per share of LP unit - basic (in dollars per share)   $ 1.09   $ (1.54)
Net income (loss) per share of common stock - diluted (in dollars per share) $ (0.99)   $ (3.18)  
Net income (loss) per share of LP unit - diluted (in dollars per share)   $ 1.08   $ (1.54)
Deferred stock / units        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Effect of dilutive stock / units (in shares) 0 62 0 0
Performance stock units / units        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Effect of dilutive stock / units (in shares) 0 80 0 0
Restricted stock / units        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Effect of dilutive stock / units (in shares) 0 487 0 0