General - Basis of Presentation (Details) $ / shares in Units, shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) park $ / shares shares	Jun. 30, 2016 USD ($) $ / shares shares	Jun. 30, 2017 USD ($) park $ / shares shares	Jun. 30, 2016 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)
Organization, Consolidation and Presentation of Financial Statements
Number of parks owned or operated | park	20		20
Income Taxes
Valuation allowance	$ 94,200,000		$ 94,200,000		$ 92,300,000
Accrued interest and penalties, income taxes	0		0		0
Excess tax benefits	1,400,000		7,500,000
Adjustment to retained earnings to recognize net operating loss carryforwards attributable to excess tax benefits on stock compensation					101,057,000
Earnings Per Share, Basic and Diluted [Abstract]
Net loss attributable to Six Flags Entertainment Corporation	$ 52,026,000	$ 60,887,000	$ (5,522,000)	$ 13,952,000
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted-average common shares outstanding — basic: | shares	87,136	93,054	89,133	92,707
Effect of dilutive stock options and restricted shares | shares	1,696	2,358	0	2,246
Weighted-average common shares outstanding — diluted: | shares	88,832	95,412	89,133	94,953
Net income per average common share outstanding — basic: | $ / shares	$ 0.60	$ 0.65	$ (0.06)	$ 0.15
Net income per average common share outstanding — diluted: | $ / shares	$ 0.59	$ 0.64	$ (0.06)	$ 0.15
Antidilutive stock options excluded from computation of diluted shares outstanding (in shares) | shares	387	27	5,020	306
Accounts Receivable, Net
Allowance for doubtful accounts	$ 12,900,000		$ 12,900,000		$ 3,000,000
United States
Organization, Consolidation and Presentation of Financial Statements
Number of parks owned or operated | park	17		17
Mexico
Organization, Consolidation and Presentation of Financial Statements
Number of parks owned or operated | park	2		2
Canada
Organization, Consolidation and Presentation of Financial Statements
Number of parks owned or operated | park	1		1