Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Total revenues	$ 459,787	$ 19,143	$ 541,811	$ 121,646
Operating expenses (excluding depreciation and amortization shown separately below)	183,768	62,681	276,411	168,545
Selling, general and administrative expenses	50,205	36,820	86,331	73,010
Costs of products sold	39,194	2,214	46,409	9,974
Other net periodic pension benefit	(1,690)	(994)	(3,333)	(1,990)
Depreciation	28,047	29,032	56,874	59,095
Amortization	5	402	11	1,003
Loss on disposal of assets	719	513	1,239	393
Interest expense	38,113	51,248	76,573	78,734
Interest income	(65)	(201)	(105)	(530)
Loss on debt extinguishment		5,087		6,106
Other expense, net	831	4,252	8,450	5,812
Income (loss) before income taxes	120,660	(171,911)	(7,049)	(278,506)
Income tax expense (benefit)	29,257	(55,661)	(2,613)	(77,710)
Net income (loss)	91,403	(116,250)	(4,436)	(200,796)
Less: Net income attributable to noncontrolling interests	(20,883)	(20,644)	(20,883)	(20,644)
Net income (loss) attributable to Six Flags Entertainment Corporation	$ 70,520	$ (136,894)	$ (25,319)	$ (221,440)
Weighted-average common shares outstanding:
Weighted-average common shares outstanding-basic (in shares)	85,673	84,704	85,437	84,680
Weighted-average common shares outstanding - diluted (in shares)	86,751	84,704	85,437	84,680
Net (loss) earnings per average common share outstanding:
Earnings (loss) per average common share outstanding - Basic (in dollars per share)	$ 0.82	$ (1.62)	$ (0.30)	$ (2.62)
Earnings (loss) per average common share outstanding - Diluted (in dollars per share)	$ 0.81	$ (1.62)	$ (0.30)	(2.62)
Cash dividends declared per common share				$ 0.25
Park admissions
Total revenues	$ 245,165	$ 10,962	$ 289,499	$ 70,768
Park food, merchandise and other
Total revenues	198,897	4,523	230,121	34,329
Sponsorship international agreements and accommodations
Total revenues	$ 15,725	$ 3,658	$ 22,191	$ 16,549