Commitments and Contingencies (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended			1 Months Ended				9 Months Ended	1 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended
	Dec. 31, 2011 partnership	Sep. 30, 2012	Apr. 01, 1998	Dec. 31, 2011 TW Loan	Dec. 31, 2011 Term Loan B	May 31, 2012 Six Flags Over Georgia (SFOG) and Six Flags Over Texas (SFOT)	May 31, 2012 Six Flags Over Georgia (SFOG)	Sep. 30, 2012 Six Flags Over Georgia (SFOG) multiplier	May 31, 2012 Six Flags Over Texas (SFOT)	May 31, 2011 Six Flags Over Texas (SFOT)	Sep. 30, 2012 Six Flags Over Texas (SFOT) multiplier	Sep. 30, 2012 Obligations guaranteed of general partner Y	Dec. 31, 2012 Obligations guaranteed of general partner Minimum	Sep. 30, 2012 Obligations guaranteed of subsidiaries Y	Sep. 30, 2012 Obligations guaranteed of subsidiaries Maximum
Details of commitments and contingencies
Acquisition of capital stock of the former Six Flags Entertainment Corporation, paid in cash			$ 976.0
Annual distributions by general partners to limited partners in partnership parks													65.1
Share of Partnership Parks' annual distributions paid to Six Flags Entertainment Corporation												28.3
Rolling period for making minimum capital expenditure at each of the Partnership Parks (in years)												5
Percentage of capital expenditures to Partnership Parks' revenues												6.00%
Percentage of amount purchased to total limited partnership units outstanding per annum															5.00%
Weighted average period of the park's EBITDA for calculation of value of purchase price (in years)														4
Specified multiple for purchase price valuation (in multipliers)								8.0			8.5
Specified price for purchase of partnership parks								250.0			374.8
Limited partner interests owned (as a percent)								30.50%			53.00%
Remaining redeemable units (as a percent)								69.50%			47.00%
Current redemption value for limited partnership units		348.2
Maximum unit purchase obligation for current year		348.2
Units purchased in partnership parks (in shares)							0.79		0.05	0.61
Units purchased pursuant to annual offer						2.0				0.9
Debt facility terminated				150.0
Accordion feature available for borrowing for future put obligations					300
Escrow deposit		15.0
Capital expenditures incurred on parks	11.2
Estimated capital expenditures on partnership parks in the next fiscal year		5.0
Number of partnerships	2
Cash generated from operating activities by partnerships, after deduction of capital expenditures and excluding the impact of short-term intercompany advances	61.1
Total loans receivable from the partnerships that own partnership parks	$ 239.3	$ 239.3