Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands	Common stock	Capital in excess of par value	Accumulated deficit	Accumulated other comprehensive loss	Total
Beginning balance at Dec. 31, 2020	$ 2,126	$ 1,089,199	$ (2,153,368)	$ (96,504)	$ (1,158,547)
Beginning balance (in shares) at Dec. 31, 2020	85,075,901
Increase (Decrease) in Equity (Deficit)
Issuance of common stock	$ 21	11,374			11,395
Issuance of common stock (in shares)	823,836
Stock-based compensation		9,638			9,638
Payment of tax withholdings on equity-based compensation through shares withheld	$ (1)	(2,178)			(2,179)
Payment of tax withholdings on equity-based compensation through shares withheld (in shares)	(49,454)
Employee stock purchase plan	$ 1	647			648
Employee stock purchase plan (in shares)	21,673
Fresh start valuation adjustment for partnership park units purchased			194		194
Net income (loss) attributable to Six Flags Entertainment Corporation			(25,319)		(25,319)
Net other comprehensive income (loss), net of tax				4,016	4,016
Ending balance at Jul. 04, 2021	$ 2,147	1,108,680	(2,178,493)	(92,488)	(1,160,154)
Ending balance (in shares) at Jul. 04, 2021	85,871,956
Beginning balance at Apr. 04, 2021	$ 2,134	1,104,904	(2,249,207)	(94,295)	(1,236,464)
Beginning balance (in shares) at Apr. 04, 2021	85,369,434
Increase (Decrease) in Equity (Deficit)
Issuance of common stock	$ 13	2,303			2,316
Issuance of common stock (in shares)	530,239
Stock-based compensation		3,001			3,001
Payment of tax withholdings on equity-based compensation through shares withheld	$ (1)	(2,178)			(2,179)
Payment of tax withholdings on equity-based compensation through shares withheld (in shares)	(49,454)
Employee stock purchase plan	$ 1	650			651
Employee stock purchase plan (in shares)	21,737
Fresh start valuation adjustment for partnership park units purchased			194		194
Net income (loss) attributable to Six Flags Entertainment Corporation			70,520		70,520
Net other comprehensive income (loss), net of tax				1,807	1,807
Ending balance at Jul. 04, 2021	$ 2,147	1,108,680	(2,178,493)	(92,488)	(1,160,154)
Ending balance (in shares) at Jul. 04, 2021	85,871,956
Beginning balance at Jan. 02, 2022	$ 2,154	1,120,084	(2,023,251)	(81,187)	(982,200)
Beginning balance (in shares) at Jan. 02, 2022	86,162,879
Increase (Decrease) in Equity (Deficit)
Issuance of common stock	$ 7	1,032			1,039
Issuance of common stock (in shares)	303,409
Stock-based compensation		7,448			7,448
Repurchase of common stock	$ (87)	(25,394)	(71,293)		(96,774)
Repurchase of common stock (in shares)	(3,464,385)
Payment of tax withholdings on equity-based compensation through shares withheld		(260)			(260)
Payment of tax withholdings on equity-based compensation through shares withheld (in shares)	(7,340)
Employee stock purchase plan	$ 1	624			625
Employee stock purchase plan (in shares)	31,993
Fresh start valuation adjustment for partnership park units purchased			117		117
Net income (loss) attributable to Six Flags Entertainment Corporation			(20,270)		(20,270)
Net other comprehensive income (loss), net of tax				9,255	9,255
Ending balance at Jul. 03, 2022	$ 2,075	1,103,534	(2,114,697)	(71,932)	(1,081,020)
Ending balance (in shares) at Jul. 03, 2022	83,026,556
Beginning balance at Apr. 03, 2022	$ 2,156	1,124,603	(2,088,913)	(75,622)	(1,037,776)
Beginning balance (in shares) at Apr. 03, 2022	86,248,545
Increase (Decrease) in Equity (Deficit)
Issuance of common stock	$ 5	735			740
Issuance of common stock (in shares)	215,707
Stock-based compensation		3,223			3,223
Repurchase of common stock	$ (87)	(25,394)	(71,293)		(96,774)
Repurchase of common stock (in shares)	(3,464,385)
Payment of tax withholdings on equity-based compensation through shares withheld		(257)			(257)
Payment of tax withholdings on equity-based compensation through shares withheld (in shares)	(5,304)
Employee stock purchase plan	$ 1	624			625
Employee stock purchase plan (in shares)	31,993
Fresh start valuation adjustment for partnership park units purchased			117		117
Net income (loss) attributable to Six Flags Entertainment Corporation			45,392		45,392
Net other comprehensive income (loss), net of tax				3,690	3,690
Ending balance at Jul. 03, 2022	$ 2,075	$ 1,103,534	$ (2,114,697)	$ (71,932)	$ (1,081,020)
Ending balance (in shares) at Jul. 03, 2022	83,026,556