Six Flags Entertainment 10-Q 28 Jul 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jul. 04, 2021	Jul. 23, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jul. 4, 2021
Entity Registrant Name	Six Flags Entertainment Corporation
Entity File Number	1-13703
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3995059
Entity Address, Address Line One	1000 Ballpark Way Suite 400
Entity Address, City or Town	Arlington
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	76011
City Area Code	972
Local Phone Number	595-5000
Title of 12(b) Security	Common stock, $0.025 par value per share
Trading Symbol	SIX
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		85,872,819
Entity Central Index Key	0000701374
Current Fiscal Year End Date	--01-02
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020	Jun. 30, 2020
Current assets:
Cash and cash equivalents	$ 252,887	$ 157,760	$ 295,956
Accounts receivable, net	124,846	36,610	47,003
Inventories	36,038	39,191	43,456
Prepaid expenses and other current assets	66,094	73,179	76,760
Total current assets	479,865	306,740	463,175
Property and equipment, net:
Property and equipment, at cost	2,445,453	2,408,690	2,385,757
Accumulated depreciation	(1,205,950)	(1,157,403)	(1,100,862)
Total property and equipment, net	1,239,503	1,251,287	1,284,895
Other assets:
Right-of-use operating leases, net	193,254	196,711	199,877
Debt issuance costs	5,966	7,034	7,451
Deposits and other assets	6,006	7,103	9,709
Goodwill	659,618	659,618	659,618
Intangible assets, net of accumulated amortization of $249, $238 and $24,227 as of July 4, 2021, December 31, 2020 and June 30, 2020, respectively	344,187	344,198	344,209
Total other assets	1,209,031	1,214,664	1,220,864
Total assets	2,928,399	2,772,691	2,968,934
Current liabilities:
Accounts payable	65,526	26,582	27,457
Accrued compensation, payroll taxes and benefits	47,846	22,031	16,114
Accrued insurance reserves	26,998	31,060	31,076
Accrued interest payable	25,289	60,184	34,827
Other accrued liabilities	108,330	93,369	77,253
Deferred revenue	310,441	205,125	182,386
Short-term lease liabilities	10,801	14,054	11,272
Total current liabilities	595,231	452,405	380,385
Noncurrent liabilities:
Long-term debt	2,626,082	2,622,641	2,619,929
Long-term lease liabilities	188,687	187,432	191,857
Other long-term liabilities	32,750	43,553	43,539
Deferred income taxes	102,853	101,831	159,986
Total noncurrent liabilities	2,950,372	2,955,457	3,015,311
Total liabilities	3,545,603	3,407,862	3,395,696
Redeemable noncontrolling interests	542,950	523,376	544,020
Stockholders' deficit:
Preferred stock, $1.00 par value
Common stock, $0.025 par value, 280,000,000 shares authorized; 85,871,956, 85,075,901 and 84,757,286 shares issued and outstanding at July 4, 2021, December 31, 2020 and June 30, 2020, respectively	2,147	2,126	2,119
Capital in excess of par value	1,108,680	1,089,199	1,077,948
Accumulated deficit	(2,178,493)	(2,153,368)	(1,951,428)
Accumulated other comprehensive loss, net of tax	(92,488)	(96,504)	(99,421)
Total stockholders' deficit	(1,160,154)	(1,158,547)	(970,782)
Total liabilities and stockholders' deficit	$ 2,928,399	$ 2,772,691	$ 2,968,934

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020	Jun. 30, 2020
Condensed Consolidated Balance Sheets
Accumulated amortization of intangible assets	$ 249	$ 238	$ 24,227
Preferred stock, par value (in dollars per share)	$ 1	$ 1	$ 1
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025	$ 0.025
Common stock, shares authorized (in shares)	280,000,000	280,000,000	280,000,000
Common stock, shares issued (in shares)	85,871,956	85,075,901	84,757,286
Common stock, shares outstanding (in shares)	85,871,956	85,075,901	84,757,286

Condensed Consolidated Statemen

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

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Condensed Consolidated Statements of Operations
Stock-based compensation	$ 3,001	$ 6,020	$ 9,638	$ 10,300

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 04, 2021		Jun. 30, 2020		Jul. 04, 2021		Jun. 30, 2020
Condensed Consolidated Statements of Comprehensive (Loss) Income
Net income (loss)	$ 91,403		$ (116,250)		$ (4,436)		$ (200,796)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	1,532	[1]	1,661	[1]	(441)	[2]	(12,537)	[2]
Defined benefit retirement plan	254	[3]	193	[3]	509	[4]	386	[4]
Change in cash flow hedging	21	[5]	9,148	[5]	3,948	[6]	(12,560)	[6]
Other comprehensive income (loss), net of tax	1,807		11,002		4,016		(24,711)
Comprehensive income (loss)	93,210		(105,248)		(420)		(225,507)
Less: Comprehensive income attributable to noncontrolling interests	(20,883)		(20,644)		(20,883)		(20,644)
Comprehensive income (loss) attributable to Six Flags Entertainment Corporation	$ 72,327		$ (125,892)		$ (21,303)		$ (246,151)
[1]	Foreign currency translation adjustment is presented net of tax expense of $0.3 million and $0.4 million for the three months ended July 4, 2021 and June 30, 2020 , respectively.
[2]	Foreign currency translation adjustment is presented net of tax benefit of $0.1 million and $3.3 million for the six months ended July 4, 2021 and June 30, 2020, respectively.
[3]	Defined benefit retirement plan is presented net of tax expense of $0.1 million for the three months ended July 4, 2021 and June 30, 2020, respectively.
[4]	Defined benefit retirement plan is presented net of tax expense of $0.2 million and $0.1 million for the six months ended July 4, 2021 and June 30, 2020, respectively.
[5]	Change in fair value of cash flow hedging is presented net of nominal tax expense for the three months ended July 4, 2021, and net of tax expense of $3.0 million for the three months ended June 30, 2020, respectively.
[6]	Change in fair value of cash flow hedging is presented net of tax expense of $1.3 million for the six months ended July 4, 2021 and net of tax benefit of $4.2 million for the six months ended June 30, 2020, respectively.

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Comprehensive (Loss) Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Condensed Consolidated Statements of Comprehensive (Loss) Income
Foreign currency translation adjustment, tax expense (benefit)	$ 0.3	$ 0.4	$ (0.1)	$ (3.3)
Defined benefit retirement plan, tax expense (benefit)	$ 0.1	0.1	0.2	0.1
Derivatives qualifying as hedges, tax expense (benefit)		$ 3	$ 1.3	$ (4.2)

Condensed Consolidated Statem_5

Condensed 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, 2019	$ 2,116	$ 1,066,223	$ (1,709,747)	$ (74,710)	$ (716,118)
Beginning balance (in shares) at Dec. 31, 2019	84,633,845
Increase (Decrease) in Stockholders' Deficit
Issuance of common stock	$ 2	732			734
Issuance of common stock (in shares)	82,064
Stock-based compensation		10,300			10,300
Payment of tax withholdings on equity-based compensation through shares withheld		(6)			(6)
Payment of tax withholdings on equity-based compensation through shares withheld (in shares)	(155)
Dividends declared to common shareholders			(21,165)		(21,165)
Employee stock purchase plan	$ 1	717			718
Employee stock purchase plan (in shares)	41,532
Fresh start valuation adjustment for partnership park units purchased			924		924
Change in redemption value of partnership units		(18)			(18)
Net loss attributable to Six Flags Entertainment Corporation			(221,440)		(221,440)
Net other comprehensive loss, net of tax				(24,711)	(24,711)
Ending balance at Jun. 30, 2020	$ 2,119	1,077,948	(1,951,428)	(99,421)	(970,782)
Ending balance (in shares) at Jun. 30, 2020	84,757,286
Beginning balance at Mar. 31, 2020	$ 2,116	1,070,900	(1,815,457)	(110,423)	(852,864)
Beginning balance (in shares) at Mar. 31, 2020	84,666,505
Increase (Decrease) in Stockholders' Deficit
Issuance of common stock	$ 1	311			312
Issuance of common stock (in shares)	49,276
Stock-based compensation		6,020			6,020
Dividends declared to common shareholders			(1)		(1)
Employee stock purchase plan	$ 2	717			719
Employee stock purchase plan (in shares)	41,505
Fresh start valuation adjustment for partnership park units purchased			924		924
Net loss attributable to Six Flags Entertainment Corporation			(136,894)		(136,894)
Net other comprehensive loss, net of tax				11,002	11,002
Ending balance at Jun. 30, 2020	$ 2,119	1,077,948	(1,951,428)	(99,421)	(970,782)
Ending balance (in shares) at Jun. 30, 2020	84,757,286
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 Stockholders' 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 loss attributable to Six Flags Entertainment Corporation			(25,319)		(25,319)
Net other comprehensive 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 Stockholders' 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 loss attributable to Six Flags Entertainment Corporation			70,520		70,520
Net other comprehensive 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

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ 91,403	$ (116,250)	$ (4,436)	$ (200,796)
Adjustments to reconcile net loss to net cash used in and provided by (used in) operating activities:
Depreciation and amortization			56,885	60,098
Stock-based compensation			9,638	10,300
Interest accretion on notes payable			554	605
Loss on debt extinguishment		5,087		6,106
Amortization of debt issuance costs			3,956	2,467
Other, including (gain) loss on disposal of assets			(445)	1,027
Change in accounts receivable			(88,193)	59,984
Change in inventories, prepaid expenses and other current assets			10,393	(28,792)
Change in deposits and other assets			1,099	2,959
Change in ROU operating leases			4,382	(1,753)
Change in accounts payable, deferred revenue, accrued liabilities and other long-term liabilities			175,266	40,564
Change in operating lease liabilities			(4,457)	6,780
Change in accrued interest payable			(34,895)	8,699
Deferred income taxes			(414)	(78,951)
Net cash provided by (used in) operating activities			129,333	(110,703)
Cash flows from investing activities:
Additions to property and equipment			(42,250)	(75,623)
Property insurance recoveries				2,514
Proceeds from sale of assets			41
Net cash used in investing activities			(42,209)	(73,109)
Cash flows from financing activities:
Repayment of borrowings			(2,000)	(526,510)
Proceeds from borrowings			2,000	884,000
Payment of debt issuance costs				(21,462)
Payment of cash dividends			(210)	(21,418)
Proceeds from issuance of common stock			11,784	1,452
Payment of tax withholdings on equity-based compensation through shares withheld			(2,179)	(6)
Reduction in finance lease liability			(350)	(184)
Purchase of redeemable noncontrolling interest			(1,115)	(4,976)
Net cash provided by financing activities			7,930	310,896
Effect of exchange rate on cash			73	(5,307)
Net change in cash and cash equivalents			95,127	121,777
Cash and cash equivalents at beginning of period			157,760	174,179	$ 174,179
Cash and cash equivalents at end of period	$ 252,887	$ 295,956	252,887	295,956	$ 157,760
Supplemental cash flow information
Cash paid for interest			107,855	52,462
Cash paid for income taxes			$ 564	$ 2,326

General - Basis of Presentation

General - Basis of Presentation	6 Months Ended
	Jul. 04, 2021
General - Basis of Presentation
General - Basis of Presentation	1. General — Basis of Presentation We own and operate regional theme parks and waterparks. We are the largest regional theme park operator in the world, and we are the largest operator of waterparks in North America based on the number of parks we operate. Of the 27 parks we owned or operated as of July 4, 2021, 24 parks are located in the United States, two are located in Mexico and one is located in Montreal, Canada. Our waterpark at Six Flags Great America, in Gurnee, Illinois, opened as a separate gate in 2021 as Hurricane Harbor Chicago, creating our 27 th The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP"). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed, or omitted, pursuant to the rules and regulations of the SEC. The Board of Directors of Six Flags Entertainment Corporation (“Holdings”) determined that it is in our best interest to change the method of determining our fiscal quarters and fiscal years, such that each fiscal quarter will consist of thirteen weeks ending on a Sunday and each fiscal year will consist of 52 or 53 weeks, as applicable, and will end on the Sunday closest to December 31, effective as of the commencement of our fiscal year on January 1, 2021. This change was made to align our reporting calendar with how we operate our business and improve comparability across periods. Our current fiscal year will end on January 2, 2022. This Quarterly Report covers the period January 1, 2021 through July 4, 2021 (“the six months ended July 4, 2021”) and the three month period from April 5, 2021 through July 4, 2021 (“the three months ended July 4, 2021”). The comparison period in the prior year covers the dates January 1, 2020 through June 30, 2020 (“the six months ended June 30, 2020”) and April 1, 2020 through June 30, 2020 (“the three months ended June 30, 2020”). The 2020 Annual Report includes additional information about us, our operations and our financial position, and should be referred to in conjunction with this Quarterly Report. The information furnished in this Quarterly Report reflects all normal and recurring adjustments that are, in the opinion of management, necessary to present a fair statement of the results for the periods presented. Results of operations for the six months ended July 4, 2021, are not indicative of the results expected for the full year. In particular, our park operations contribute more than half of their annual revenue during the period from Memorial Day to Labor Day each year, while expenses are incurred year-round. COVID-19 Considerations In response to the COVID-19 pandemic, federal, state and local governments implemented significant restrictions on travel, social conduct and business operations, including mass quarantine and social distancing mandates and orders. In March 2020, we quickly implemented plans to mitigate the impact of the COVID-19 pandemic on our business to ensure the health and safety of our employees and guests. We resumed partial operations at many of our parks on a staggered basis near the end of the second quarter of 2020 using a cautious and phased approach, including limiting attendance, in accordance with local conditions and government guidelines. Attendance trends continued to improve throughout 2020 and the first half of 2021. As of May 29, 2021, we had opened all of our parks, and, as of June 15, 2021, none of our parks were subject to mandated capacity constraints, with the exception of our theme park in Montreal and our two parks in Mexico. The COVID-19 pandemic has had and may continue to have an unfavorable impact on certain parts of our business. The broader implications of the COVID-19 pandemic on our business, financial condition and results of operations remain uncertain and will depend on certain developments, including the duration and severity of the COVID-19 pandemic, the impact of virus variants, the rate of vaccinations, and the COVID-19 pandemic’s impact on our guests and suppliers. We have taken measures to ensure sufficient liquidity to meet our cash flow needs and covenant compliance obligations for at least the next twelve months from the issuance of these financial statements. Additionally, we believe we have sufficient liquidity to meet our cash obligations through the end of 2021 even if we are required to suspend operations due to the COVID-19 pandemic. In addition to reducing expenses and capital expenditures, in April 2020, we increased the revolving credit commitments under the Second Amended and Restated Revolving Loan by $131.0 million, increasing the facility from $350.0 million to $481.0 million. Also, in April 2020, Six Flags Theme Parks Inc. (“SFTP”), Holdings’ indirect, wholly owned subsidiary, completed the private sale of $725.0 million in aggregate principal amount of 7.00% senior secured notes due 2025. In August 2020, we extended the increased revolving credit commitments under the Second Amended and Restated Revolving Loan through December 31, 2022, and extended the suspension of the senior secured leverage ratio financial maintenance covenant through the end of 2021. See Note 3, Long-Term Indebtedness The COVID-19 pandemic continues to present material uncertainty and risk with respect to our performance and financial results, including our ability to keep all of our parks open to our guests. We will continue to consider near-term exigencies and the long-term financial health of the business as we take steps to mitigate the consequences of the COVID-19 pandemic on our business. The extent to which the COVID-19 pandemic impacts our business will depend on future developments, which are highly uncertain and cannot be predicted, including any additional actions we have taken, or will take, to minimize the spread of COVID-19 or manage its impact. Our business and financial results could be materially and adversely impacted. Transformation Plan ​ ​ ​ ​ ​ ​ ​ ​ Transformation Costs Breakout by Quarter ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ July 4, 2021 ​ July 4, 2021 Amounts included in "Other expense, net" ​ ​ ​ ​ ​ ​ Consultant costs ​ $ 67 ​ $ 6,854 Technology modernization costs ​ ​ 976 ​ ​ 3,070 Employee termination costs ​ ​ 293 ​ ​ 1,108 Total transformation costs ​ $ 1,336 ​ $ 11,032 ​ ​ a. Consolidated U.S. GAAP Presentation Our accounting policies reflect industry practices and conform to U.S. GAAP. The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly owned subsidiaries. We also consolidate the partnerships that own Six Flags Over Texas ("SFOT") and Six Flags Over Georgia (including Six Flags White Water Atlanta) ("SFOG", and together with SFOT, the "Partnership Parks") as subsidiaries in our unaudited condensed consolidated financial statements, as we have determined that we have the power to direct the activities of the Partnership Parks that most significantly impact their economic performance and we have the obligation to absorb losses and receive benefits from the Partnership Parks that can be potentially significant to these entities. The equity interests owned by non-affiliated parties in the Partnership Parks are reflected in the accompanying unaudited condensed consolidated balance sheets as redeemable noncontrolling interests. See Note 6 for a description of the partnership agreements applicable to the Partnership Parks and Note 8 for further discussion on the non-affiliated parties’ share of the earnings of the Partnership Parks. b. Income Taxes We recorded a valuation allowance of $129.4 million, $128.2 million and $134.1 million as of July 4, 2021, December 31, 2020, and June 30, 2020, respectively, due to uncertainties related to our ability to use some of our deferred tax assets, primarily consisting of certain state net operating loss and other tax carryforwards, before they expire. The valuation allowance was based on our estimates of taxable income by jurisdiction in which we operate and the period over which our deferred tax assets were recoverable. Our projected taxable income over the foreseeable future indicates we will be able to use all of our federal net operating loss carryforwards before they expire. We classify interest and penalties attributable to income taxes as part of income tax expense. As of July 4, 2021, December 31, 2020, and June 30, 2020, we had no recorded amounts for accrued interest or penalties. c. Goodwill and Intangibles Goodwill and intangible assets with indefinite lives are tested for impairment annually, or more frequently if events or circumstances indicate that the assets might be impaired. We identify our reporting unit and determine the carrying value of the reporting unit by assigning the assets and liabilities, including the existing goodwill and intangible assets, to the reporting unit. We then determine the fair value of the reporting unit and compare it to the carrying amount of the reporting unit. All of our parks are operated in a similar manner and have comparable characteristics in that they produce and distribute similar services and products using similar processes, have similar types of customers, are subject to similar regulations and exhibit similar economic characteristics. As such, we are a single reporting unit. As of July 4, 2021, the fair value of the single reporting unit exceeded our carrying amount. We have one reporting unit at the same level for which Holdings common stock is traded and we believe our market capitalization is the best indicator of our reporting unit’s fair value. At July 4, 2021, we determined that it is not more likely than not that the fair value of our intangible assets were less than their carrying amounts and there were no triggering events. d. Long-Lived Assets We review long-lived assets, including finite-lived intangible assets subject to amortization, for impairment upon the occurrence of events or changes in circumstances that would indicate that the carrying value of the asset or group of assets may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of the asset or group of assets to the future net cash flows expected to be generated by the asset or group of assets. If such assets are not considered to be fully recoverable, any impairment to be recognized is measured by the amount by which the carrying amount of the asset or group of assets exceeds its respective fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. We determined that our long-lived assets were recoverable as of July 4, 2021. e. Earnings (loss) Per Common Share Earnings (loss) per common share for the three and six months ended July 4, 2021, and June 30, 2020, was calculated as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended (Amounts in thousands, except per share data) July 4, 2021 June 30, 2020 July 4, 2021 June 30, 2020 Net income (loss) attributable to Six Flags Entertainment Corporation $ 70,520 ​ $ (136,894) $ (25,319) ​ $ (221,440) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding - basic: ​ ​ 85,673 ​ ​ 84,704 ​ ​ 85,437 ​ ​ 84,680 Effect of dilutive stock options and restricted stock units ​ ​ 1,078 ​ ​ — ​ ​ — ​ ​ — Weighted-average common shares outstanding - diluted: ​ ​ 86,751 ​ ​ 84,704 ​ ​ 85,437 ​ ​ 84,680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings (loss) per share - basic: ​ $ 0.82 ​ $ (1.62) ​ $ (0.30) ​ $ (2.62) Earnings (loss) per share - diluted: ​ $ 0.81 ​ $ (1.62) ​ $ (0.30) ​ $ (2.62) ​ ​ f. Stock Benefit Plans Pursuant to the Six Flags Entertainment Corporation Long-Term Incentive Plan (the "Long-Term Incentive Plan"), Holdings may grant stock options, stock appreciation rights, restricted stock, restricted stock units, unrestricted stock, deferred stock units, performance and cash-settled awards and dividend equivalent rights ("DERs") to select employees, officers, directors and consultants of Holdings and its affiliates. During the six months ended July 4, 2021, performance stock units were granted to key employees that will vest upon the achievement of specified EBITDA and revenue performance targets by 2023. The aggregate payout under these awards if the targets are achieved in 2023 would be 186,000 shares of Holdings’ common stock, but could be more or less depending on the level of achievement and timing thereof. There has been no stock-based compensation expense recorded for the performance stock units because, as of July 4, 2021, it is not deemed probable that we will achieve the specified performance targets in 2023. Based on the grant date fair value of these performance stock units as determined by the closing market price of Holdings’ common stock on the date of grant, the total unrecognized compensation cost related to these performance stock units at target achievement in 2023 is $9.3 million, which will be expensed over the service period if achievement of the performance conditions becomes probable. We will continue to evaluate the probability of achieving the performance conditions going forward, and will record the appropriate expense as necessary. ​ During the three and six months ended July 4, 2021, and June 30, 2020, stock-based compensation expense consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended (Amounts in thousands) July 4, 2021 June 30, 2020 July 4, 2021 June 30, 2020 Long-Term Incentive Plan ​ $ 2,785 ​ $ 6,015 ​ $ 9,347 ​ $ 10,220 Employee Stock Purchase Plan ​ 216 ​ 5 ​ 291 ​ 80 Total Stock-Based Compensation ​ $ 3,001 ​ $ 6,020 ​ $ 9,638 ​ $ 10,300 ​ g. Accounts Receivable, Net Accounts receivable are reported at net realizable value and consist primarily of amounts due from guests for the sale of group outings and multi-use admission products, such as season passes and the membership program. We are not exposed to a significant concentration of credit risk; however, based on the age of the receivables, our historical experience and other factors and assumptions we believe to be customary and reasonable, we record an allowance for doubtful accounts. As of July 4, 2021, December 31, 2020, and June 30, 2020, we have recorded an allowance for doubtful accounts of $29.8 million, $3.1 million and $6.4 million, respectively, which is primarily comprised of estimated payment defaults under our membership program. To the extent that payments under our membership program have not been recognized in revenue, the allowance for doubtful accounts recorded against our membership program is offset with a corresponding reduction in deferred revenue. h. Recently Adopted Accounting Pronouncements In December 2019, FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“Update 2019-12”) i. Recent Accounting Pronouncements In August 2018, FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans: (“Update 2018-14”) In March 2020, FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting

Revenue

Revenue	6 Months Ended
	Jul. 04, 2021
Revenue
Revenue	2. Revenue Revenues are recognized when control of the promised goods or services is transferred to our customers in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Sales and other taxes we collect concurrent with revenue-producing activities are excluded from revenue. Incidental items that are immaterial in the context of the contract are recognized as expense. The following tables present our revenues disaggregated by contract duration for the three and six month periods ended July 4, 2021, and June 30, 2020, respectively. Long-term and short-term contracts consist of our contracts with customers with terms greater than one year and less than or equal to one year, respectively. Sales and usage-based taxes are excluded from revenues. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended July 4, 2021 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ ​ ​ Park Food, ​ International ​ ​ ​ ​ ​ ​ ​ ​ Merchandise ​ Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 69,784 ​ $ 6,826 ​ $ 8,741 ​ $ 85,351 Short-term contracts and other (a) ​ 175,381 ​ 192,071 ​ 6,984 ​ 374,436 Total revenues ​ $ 245,165 ​ $ 198,897 ​ $ 15,725 ​ $ 459,787 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, 2020 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ (3,061) ​ $ (163) ​ $ 3,580 ​ $ 356 Short-term contracts and other (a) ​ 14,023 ​ 4,686 ​ 78 ​ 18,787 Total revenues ​ $ 10,962 ​ $ 4,523 ​ $ 3,658 ​ $ 19,143 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended July 4, 2021 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 76,794 ​ $ 7,823 ​ $ 12,904 ​ $ 97,521 Short-term contracts and other (a) ​ 212,705 ​ 222,298 ​ 9,287 ​ 444,290 Total revenues ​ $ 289,499 ​ $ 230,121 ​ $ 22,191 ​ $ 541,811 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, 2020 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 2,701 ​ $ 657 ​ $ 12,850 ​ $ 16,208 Short-term contracts and other (a) ​ 68,067 ​ 33,672 ​ 3,699 ​ 105,438 Total revenues ​ $ 70,768 ​ $ 34,329 ​ $ 16,549 ​ $ 121,646 (a) Other revenues primarily include sales of single-day tickets and short-term transactional sales for which we have the right to invoice. ​ Long-term Contracts Our long-term contracts consist of season passes purchased by customers in the year preceding the operating season to which they relate, sponsorship contracts and international agreements with third parties. Due to the COVID-19 pandemic, we have extended all 2020 season passes through the 2021 season. Due to the extension of term on the 2020 season passes, all 2020 season passes have a length greater than one year and are thus considered long-term contracts. We earn season pass revenue when our customers purchase a season pass for a fixed fee, which entitles the customer to visit our parks, including certain waterparks, throughout the duration of the parks’ operating season. We earn sponsorship revenue from separately-priced contracts with third parties pursuant to which we sell and advertise the third party’s products within the parks in exchange for consideration. Advertisements may include, but are not limited to, banners, signs, radio ads, association with certain events, sponsorship of rides within our parks and retail promotions. We earn international agreements revenue pursuant to arrangements in which we assist in the development and management of Six Flags-branded parks outside of North America. Within our international agreements, we have identified three distinct performance obligations as brand licensing, project services and management services. We do not consider revenue recognized for the performance obligations related to our international agreements to be significant, neither individually nor in the aggregate, to any period presented. At January 1, 2021, $77.6 million of unearned revenue associated with outstanding long-term contracts was reported in "Deferred revenue," of which $26.6 million and $35.0 million was recognized as revenue for long-term contracts during the three and six months ended July 4, 2021, respectively. As of July 4, 2021, the total unearned amount of revenue for remaining long-term contract performance obligations was $112.6 million. At January 1, 2020, $85.1 million of unearned revenue associated with outstanding long-term contracts was reported in "Deferred revenue," of which $4.0 million and $19.6 million was recognized as revenue for long-term contracts during the three and six months ended June 30, 2020, respectively. As of June 30, 2020, the total unearned amount of revenue for remaining long-term contract performance obligations was $79.3 million. 2021 2022 2023 2024 2025

Long-Term Indebtedness

Long-Term Indebtedness	6 Months Ended
	Jul. 04, 2021
Long-Term Indebtedness
Long-Term Indebtedness	3. Long-Term Indebtedness Credit Facility As of July 4, 2021, our credit facility consisted of a $481.0 million revolving credit loan facility (the “Second Amended and Restated Revolving Loan”) and a $479.0 million Tranche B Term Loan facility (the “Second Amended and Restated Term Loan B”) pursuant to the amended and restated credit facility that we entered into in 2019 (the “Second Amended and Restated Credit Facility”) and further amended in both April 2020 and August 2020. As of July 4, 2021, December 31, 2020 and June 30, 2020, no advances under the Second Amended and Restated Revolving Loan were outstanding (excluding amounts reserved for letters of credit in the amount of $20.2 million, $20.8 million and $21.3 million, respectively). Interest on the Second Amended and Restated Revolving Loan accrues at an annual rate of LIBOR plus an applicable margin with an unused commitment fee based on our senior secured leverage ratio. As of July 4, 2021, the Second Amended and Restated Revolving Loan unused commitment fee was 0.625%. The Second Amended and Restated Revolving Loan matures on April 17, 2024. As of July 4, 2021, December 31, 2020 and June 30, 2020, $479.0 million was outstanding under the Second Amended and Restated Term Loan B. Interest on the Second Amended and Restated Term Loan B accrues at an annual rate of LIBOR plus 1.75%. In June 2019, we entered into swap agreements with an aggregate notional value of $300 million In conjunction with a $315.0 million repayment of the Second Amended and Restated Term Loan B in April 2020, certain of our interest rate swap agreements were de-designated as the hedged interest was no longer probable to occur. We hold and issue derivative instruments for risk management purposes only and do not utilize derivative instruments for trading or speculative purposes. Accordingly, in April 2020 we entered into counter-agreements to economically offset the impact of the de-designated swap agreements. ​ 2024 Notes, 2025 Notes and 2027 Notes In June 2016, Holdings issued $300.0 million of 4.875% senior unsecured notes due 2024 and, in April 2017, issued an additional $700.0 million of senior unsecured notes due 2024 (together, the “2024 Notes”). In April 2017, Holdings issued $500.0 million of 5.50% senior notes due 2027 (the "2027 Notes"). In April 2020, SFTP issued $725.0 million of 7.00% senior secured notes due 2025 (the “2025 Notes”). As of July 4, 2021, $949.5 million of the 2024 Notes, $725.0 million of the 2025 Notes, and $500.0 million of the 2027 Notes, were issued and outstanding. Interest payments of $23.1 million for the 2024 Notes are due semi-annually on January 31 and July 31 of each year. Interest payments of $25.4 million for the 2025 Notes are due semi-anually on January 1 and July 1 each year. Interest payments of $13.8 million for the 2027 Notes are due semi-annually on April 15 and October 15 of each year. Long-Term Indebtedness Summary As of July 4, 2021, December 31, 2020 and June 30, 2020, the principal balance of our long-term debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) July 4, 2021 December 31, 2020 June 30, 2020 Second Amended and Restated Term Loan B $ 479,000 $ 479,000 $ 479,000 2024 Notes ​ 949,490 ​ 949,490 ​ 949,490 2025 Notes ​ ​ 725,000 ​ ​ 725,000 ​ ​ 725,000 2027 Notes ​ 500,000 ​ 500,000 ​ 500,000 Net discount ​ (3,803) ​ (4,357) ​ (4,910) Deferred financing costs ​ (23,605) ​ (26,492) ​ (28,651) Total long-term debt ​ $ 2,626,082 ​ $ 2,622,641 ​ $ 2,619,929 ​ Fair-Value of Long-Term Indebtedness As of July 4, 2021, December 31, 2020 and June 30, 2020, the fair value of our long-term debt was $2,705.3 million, $2,693.3 million and $2,463.7 million, respectively.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jul. 04, 2021
Accumulated Other Comprehensive Loss.
Accumulated Other Comprehensive Loss	Changes in the composition of Accumulated Other Comprehensive Loss ("AOCI") during the six months ended July 4, 2021 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other ​ ​ Translation ​ Cash Flow ​ Defined Benefit ​ Income ​ Comprehensive (Amounts in thousands) Adjustment Hedges Plans Taxes Loss Balances at December 31, 2020 ​ $ (27,412) ​ $ (16,819) ​ $ (57,642) ​ $ 5,369 ​ $ (96,504) Net current period change ​ (462) ​ 2,529 ​ — ​ (613) ​ 1,454 Amounts reclassified from AOCI ​ — ​ 2,742 ​ 680 ​ (860) ​ 2,562 Balances at July 4, 2021 ​ $ (27,874) ​ $ (11,548) ​ $ (56,962) ​ $ 3,896 ​ $ (92,488) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of Reclassification from AOCI ​ Amount of Reclassification from AOCI ​ ​ ​ ​ Three Months Ended ​ Six Months Ended Component of AOCI Location of Reclassification into (Loss) Income ​ July 4, 2021 ​ June 30, 2020 July 4, 2021 ​ June 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of loss on interest rate hedge ​ Interest expense ​ $ 1,381 ​ $ 15,972 ​ $ 2,742 ​ $ 15,852 ​ ​ Income tax benefit ​ ​ (347) ​ ​ (3,980) ​ (689) ​ (3,950) ​ ​ Net of tax ​ $ 1,034 ​ $ 11,992 ​ $ 2,053 ​ $ 11,902 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of deferred actuarial loss and prior service cost Operating expenses ​ $ 340 ​ $ 258 ​ $ 680 ​ $ 515 ​ Income tax benefit ​ (86) ​ (64) ​ (171) ​ (128) ​ Net of tax ​ $ 254 ​ $ 194 ​ $ 509 ​ $ 387 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications ​ $ 1,288 ​ $ 12,186 ​ $ 2,562 ​ $ 12,289 ​

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jul. 04, 2021
Derivative Financial Instruments
Derivative Financial Instruments	5. Derivative Financial Instruments We hold interest rate swap agreements that mitigate the risk of an increase in the LIBOR rate in effect on our Term Loan B. We enter into derivative contracts for risk management purposes only and do not utilize derivative instruments for trading or speculative purposes. As such, in conjunction with the repayment of a portion of our Term Loan B in April 2020, certain of our interest rate swap agreements were de-designated as the hedged interest was no longer probable to occur. ​ Derivative assets and derivative liabilities that have maturity dates equal to or less than twelve months from the balance sheet date are included in “Prepaid expenses and other current assets” and “Other accrued liabilities,” respectively. Derivative assets and derivative liabilities that have maturity dates greater than twelve months from the balance sheet date are included in “Deposits and other assets” and “Other long-term liabilities”, respectively. The table below presents the fair value of our derivative financial instruments in an asset position as well as their classification on the unaudited condensed consolidated balance sheets as of July 4, 2021, December 31, 2020, and June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Assets (Amounts in thousands) July 4, 2021 December 31, 2020 June 30, 2020 Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreements — current $ 833 ​ $ 877 ​ $ 655 Interest rate swap agreements — non-current ​ — ​ ​ 585 ​ ​ 677 ​ $ 833 $ 1,462 $ 1,332 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Liabilities (Amounts in thousands) ​ July 4, 2021 December 31, 2020 June 30, 2020 Derivatives Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreements — current ​ $ (5,169) $ (5,251) $ (4,639) Interest rate swap agreements — non-current ​ ​ (6,434) ​ ​ (11,633) ​ ​ (13,693) Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreements — current ​ (4,830) ​ (4,875) ​ (4,345) Interest rate swap agreements — non-current ​ ​ (6,549) ​ ​ (9,032) ​ ​ (11,395) ​ ​ $ (22,982) $ (30,791) $ (34,072) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Asset Derivatives ​ ​ ​ ​ July 4, 2021 ​ December 31, 2020 ​ June 30, 2020 ​ Balance Sheet Classifications Fair Value Fair Value Fair Value Derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other current assets ​ $ 429 ​ $ 877 ​ $ 655 Interest rate contracts ​ Other long-term liabilities ​ ​ (72) ​ ​ 585 ​ ​ 677 Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ 357 ​ $ 1,462 ​ $ 1,332 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total asset derivatives ​ ​ ​ $ 357 ​ $ 1,462 ​ $ 1,332 ​ ​ Derivative liabilities recorded at fair value in our condensed consolidated balance sheets as of July 4, 2021, December 31, 2020, and June 30, 2020, respectively, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Liability Derivatives ​ ​ ​ ​ July 4, 2021 ​ December 31, 2020 ​ June 30, 2020 ​ Balance Sheet Classifications Fair Value Fair Value Fair Value Derivatives designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other accrued liabilities ​ $ (5,169) ​ $ (5,251) ​ $ (4,639) Interest rate contracts ​ Other long-term liabilities ​ ​ (6,434) ​ ​ (11,633) ​ ​ (13,693) Total derivatives designated as hedging instruments under ASC 815 ​ ​ ​ $ (11,603) ​ $ (16,884) ​ $ (18,332) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other current assets ​ $ 404 ​ $ — ​ $ — Interest rate contracts ​ Other accrued liabilities ​ ​ (4,830) ​ ​ (4,875) ​ ​ (4,345) Interest rate contracts ​ Other long-term liabilities ​ ​ (6,478) ​ ​ (9,032) ​ ​ (11,395) Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ (10,904) ​ $ (13,907) ​ $ (15,740) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liability derivatives ​ ​ ​ $ (22,507) ​ $ (30,791) ​ $ (34,072) ​ Gains and losses before taxes on derivatives designated as hedging instruments were presented in “Interest expense” in the condensed consolidated statements of operations for the three and six months ended July 4, 2021, and June 30, 2020, were as follows: Three Months Ended July 4, 2021 and June 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss ​ Loss Reclassified from ​ ​ Recognized in AOCL ​ AOCL into Operations (Amounts in thousands) 2021 2020 2021 ​ 2020 Interest rate swap agreements ​ $ (1,354) $ (3,786) $ (1,381) $ (1,044) Total $ (1,354) $ (3,786) $ (1,381) $ (1,044) Six Months Ended July 4, 2021 and June 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (Loss) ​ Loss Reclassified from ​ ​ Recognized in AOCL ​ AOCL into Operations (Amounts in thousands) 2021 2020 2021 2020 Interest rate swap agreements ​ $ 2,529 $ (32,580) $ (2,742) $ (924) Total $ 2,529 $ (32,580) $ (2,742) $ (924) ​ As of July 4, 2021, we expect to reclassify net losses of $5.1 million, currently recorded in AOCL, into “Interest expense, net” within the next twelve months. However, the actual amount reclassified could vary due to future changes in the fair value of derivatives.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jul. 04, 2021
Commitments and Contingencies
Commitments and Contingencies	6. Commitments and Contingencies Partnership Parks We have guaranteed the obligations of the general partners of those partnerships to (i) make minimum annual distributions (including rent) of approximately $75.2 million in 2021 (subject to cost of living adjustments) to the limited partners in the Partnership Parks (based on our ownership of units as of July 4, 2021, our share of the distribution will be approximately $33.4 million) and (ii) make minimum capital expenditures at each of the Partnership Parks during rolling five-year periods, based generally on 6% of the Partnership Parks’ revenues.Pursuant to the 2021 annual offer to purchase limited partnership units tendered by the unit holders (the "Partnership Park Put"), in May 2021, we purchased 0.125 limited partnership units in the Georgia partnership for $0.5 million and we purchased 0.25 units from the Texas partnership for $0.6 million. As we purchase additional units, we are entitled to a proportionate increase in our share of the minimum annual distributions. The maximum unit purchase obligations for 2021 at both parks is approximately $522.3 million, representing approximately 68.5% of the outstanding units of SFOG and 46.0% of the outstanding units of SFOT. The agreed price for units tendered in the Partnership Park Put is based on a valuation of each of the respective Partnership Parks (the "Specified Price") that is the greater of (a) a valuation for each of the respective Partnership Parks derived by multiplying such park’s weighted average four-year EBITDA (as defined in the agreements that govern the partnerships) by a specified multiple (8.0 in the case of SFOG and 8.5 in the case of SFOT) and (b) a valuation derived from the highest prices previously offered for the units of the Partnership Parks by certain entities. In light of the temporary suspension of operations of the parks due to the COVID-19 pandemic in March 2020, which would cause the value of the Partnership Park units to decrease in 2021 and thereafter, we adjusted our annual offer to purchase these units to set a minimum price floor for all future purchases. Pursuant to the new minimum price floor, the Specified Price for the Partnership Parks, if determined as of July 4, 2021, is $409.7 million in the case of SFOG and $527.4 million in the case of SFOT. As of July 4, 2021, we owned approximately 31.5% and 54.0% of the Georgia limited partner interests and Texas limited partner interests, respectively. Our obligations with respect to SFOG and SFOT will continue until 2027 and 2028, respectively. We incurred $9.1 million of capital expenditures at the Partnership Parks during the 2020 season and intend to incur approximately $12.0 million of capital expenditures at these parks for the 2021 season, an amount in excess of the minimum required expenditure. Cash flows from operations at the Partnership Parks will be used to satisfy the annual distribution and capital expenditure requirements, before any funds are required from us. The Partnership Parks used approximately $5.0 million of cash in 2020 in operating activities, after deduction of capital expenditures and excluding the impact of short-term intercompany advances from or payments to Holdings. As of both July 4, 2021, and December 31, 2020 Redeemable noncontrolling interests represent the non-affiliated parties’ share of the assets of the Partnership Parks that are less than wholly-owned: SFOT, SFOG and Six Flags White Water Atlanta, which is owned by the partnership that owns SFOG. As of July 4, 2021, redeemable noncontrolling interests of the SFOT and SFOG partnerships was $252.3 million and $290.7 million, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) SFOT SFOG Total Balance at December 31, 2020 ​ $ 242,595 ​ $ 280,781 ​ $ 523,376 Purchase of redeemable units ​ (603) ​ (512) ​ (1,115) Fresh start accounting fair market value adjustment for purchased units ​ ​ (126) ​ ​ (68) ​ ​ (194) Net income attributable to noncontrolling interests ​ 10,433 ​ 10,450 ​ 20,883 Balance at July 4, 2021 ​ $ 252,299 ​ $ 290,651 ​ $ 542,950 ​ The redemption value of the noncontrolling partnership units in SFOT and SFOG as of July 4, 2021 was approximately $242.0 million and $280.3 million, respectively. Insurance We maintain insurance of the types and in amounts that we believe are commercially reasonable and that are available to businesses in our industry. The majority of our current insurance policies expire on December 31, 2021. We generally renegotiate our insurance policies on an annual basis. We cannot predict the level of the premiums that we may be required to pay for subsequent insurance coverage, the level of any self-insurance retention applicable thereto, the level of aggregate coverage available or the availability of coverage for specific risks. Litigation Privacy Class Action Lawsuits On January 7, 2016, a putative class action complaint was filed against Holdings in the Circuit Court of Lake County, Illinois. On April 22, 2016, Great America, LLC was added as a defendant. The complaint asserts that we violated the Illinois Biometric Information Privacy Act ("BIPA") in connection with the admission of season pass holders and members through the finger scan program that commenced in the 2014 operating season at Six Flags Great America in Gurnee, Illinois, and seeks statutory damages, attorneys’ fees and an injunction. An aggrieved party under BIPA may recover (i) $1,000 if a company is found to have negligently violated BIPA or (ii) $5,000 if found to have intentionally or recklessly violated BIPA, plus reasonable attorneys’ fees in each case. The complaint does not allege that any information was misused or disseminated. On April 7, 2017, the trial court certified two questions for consideration by the Illinois Appellate Court of the Second District. On June 7, 2017, the Illinois Appellate Court granted our motion to appeal. Accordingly, two questions regarding the interpretation of BIPA were certified for consideration by the Illinois Appellate Court. On December 21, 2017, the Illinois Appellate Court found in our favor, holding that the plaintiff had to allege more than a technical violation of BIPA and had to be injured in some way in order to have a right of action. On March 1, 2018, the plaintiff filed a petition for leave to appeal to the Illinois Supreme Court. On May 30, 2018, the Illinois Supreme Court granted the plaintiff’s leave to appeal and oral arguments were heard on November 20, 2018. On January 25, 2019, the Illinois Supreme Court found in favor of the plaintiff, holding that the plaintiff does not need to allege an actual injury beyond the violation of his rights under BIPA in order to proceed with a complaint. On May 7, 2021, the parties entered into a settlement agreement to resolve the lawsuit, and preliminary approval was granted by the court on May 14, 2021. During 2017, four putative class action complaints were filed against Holdings or one of its subsidiaries. Complaints were filed on August 11, 2017, in the Circuit Court of Lake County, Illinois; on September 1, 2017, in the United States District Court for the Northern District of Georgia; on September 11, 2017, in the Superior Court of Los Angeles County, California; and on November 30, 2017, in the Superior Court of Ocean County, New Jersey. The complaints allege that we, in violation of federal law, printed more than the last five digits of a credit or debit card number on customers’ receipts and/or the expiration dates of those cards. A willful violation may subject a company to liability for actual damages or statutory damages between $100 and $1,000 per person, punitive damages in an amount determined by a court and reasonable attorneys’ fees, all of which are sought by the plaintiffs. The complaints do not allege that any information was misused. On October 20, 2020, the parties entered into a settlement agreement to resolve the lawsuits, for an immaterial amount, and final approval was granted by the court on June 18, 2021. Securities Class Action Lawsuits ​ In February 2020, two putative securities class action complaints were filed against Holdings and certain of its former executive officers (collectively, the “defendants”) in the U.S. District Court for the Northern District of Texas. On March 2, 2020, the two cases were consolidated in an action captioned Electrical Workers Pension Fund Local 103 I.B.E.W. v. Six Flags Entertainment Corp., et al. amend or set aside judgment on March 31, 2021, which the court denied on July 26, 2021. We believe that these lawsuits are without merit and intend to defend this litigation vigorously. However, there can be no assurance regarding the ultimate outcome of the lawsuit. ​ Stockholder Derivative Lawsuits ​ On March 20, 2020, a putative stockholder derivative lawsuit was filed on behalf of nominal defendant Holdings, by Mr. Mark Schwartz in the U.S. District Court for the Northern District of Texas against certain of its current and former executive officers and directors (the “individual defendants”) in an action captioned Schwartz v. Reid-Anderson, et al. , Case No. 4:20-cv-00262-P (N.D. Tex.). In April 2020, two additional stockholder derivative lawsuits, making substantially identical allegations as the Schwartz complaint, were filed on behalf of nominal defendant Holdings by Trustees of the St. Clair County Employees’ Retirement System and Mr. Mehmet Ali Albayrak in the U.S. District Court for the Northern District of Texas in actions captioned Martin, et al. v. Reid-Anderson, et al. , Case No. 4:20-cv-00311-P (N.D. Tex.) and Albayrak v. Reid-Anderson, et al. , Case No. 4:20-cv-00312-P (N.D. Tex.), respectively. On April 8, 2020, plaintiffs in all three of these putative derivative actions moved to consolidate the three actions and to appoint lead counsel. On May 8, 2020, the court granted the plaintiffs’ motion to consolidate. The consolidated action is captioned In re Six Flags Entertainment Corporation Derivative Litigation , Case No. 4:20-cv-00262-P (N.D. Tex.). On August 10, 2020, plaintiffs filed a consolidated derivative complaint. The consolidated derivative complaint alleges breach of fiduciary duty, insider selling, waste of corporate assets, unjust enrichment, and contribution for violations of federal securities laws. The consolidated derivative complaint references, and makes many of the same allegations, as are set forth in the Electrical Workers litigation, alleging, among other things, that the individual defendants breached their fiduciary duties, committed waste, are liable for contribution for, or were unjustly enriched by making, failing to correct, or failing to implement adequate internal controls relating to alleged materially false or misleading statements or omissions regarding the Company’s business, operations and growth prospects, specifically with respect to the prospects of the development of its Six Flags branded parks in China and the financial health of its partner, Riverside Investment Group Co. Ltd. The consolidated derivative complaint also alleges that a former officer and director sold shares of the Company while allegedly in possession of material non-public information concerning the same. On September 9, 2020, Holdings and the individual defendants filed a motion to dismiss the consolidated complaint. On April 28, 2021, the court granted defendants’ motion, dismissing the consolidated complaint in its entirety and with prejudice and denying leave to amend. Plaintiffs’ time to appeal the judgment dismissing this action in its entirety and with prejudice and denying leave to amend lapsed in May 2021. ​ On May 5, 2020, a putative stockholder derivative lawsuit was filed on behalf of nominal defendant Holdings, by Mr. Richard Francisco in the District Court for Dallas County, Texas, 160th Judicial District, against certain of its current and former executive officers and directors (the “individual defendants”) in an action captioned Francisco v. Reid-Anderson, et al. , Case No. DC-20-06425 (160th Dist. Ct., Dallas Cty., Tex.) (the “Francisco action”). The petition in the Francisco action alleges breach of fiduciary duty, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets. The petition in the Francisco action references, and makes many of the same allegations, as are set forth in the Electrical Workers litigation, alleging, among other things, that the individual defendants breached their fiduciary duties, were unjustly enriched by, abused their control, committed gross mismanagement, and committed waste by making, failing to correct, or failing to implement adequate internal controls relating to alleged materially false or misleading statements or omissions regarding the Company’s business, operations and growth prospects, specifically with respect to the prospects of the development of its Six Flags branded parks in China and the financial health of its partner, Riverside Investment Group Co, Ltd. The petition also alleges that a former officer and director engaged in insider trading. On May 28, 2020, the parties in the Francisco action filed a joint motion to stay proceedings through the resolution of the forthcoming motion to dismiss the Electrical Workers litigation. On June 3, 2020, the court granted the joint motion to stay proceedings. On June 12, 2020, an additional stockholder derivative lawsuit, making substantially identical allegations as the Francisco petition, was filed on behalf of nominal defendant Holdings in the District Court for Dallas County, Texas, 298th Judicial District on behalf of putative stockholder Mr. Cliff Bragdon in an action captioned Bragdon v. Reid-Anderson, et al. (298th Dist. Ct., Dallas Cty., Tex.) (the “Bragdon action”). On July 10, 2020, the court granted an agreed motion filed by the parties in the Francisco and Bragdon actions to consolidate cases, to accept service and an unopposed motion to appoint co-lead and liaison counsel, and to stay both the Francisco and Bragdon actions through resolution of the motion to dismiss the Electrical Workers litigation. The consolidated state derivative action is captioned In re Six Flags Entertainment Corp. Derivative Litigation , Case No. DC-20-06425 (160th Dist. Ct., Dallas Cty., Tex.). On September 8, 2020, the parties to the consolidated state derivative action filed an agreed motion to transfer the case from Dallas County to Tarrant County, which motion was so ordered on September 27, 2020. The consolidated action is now captioned In re Six Flags Ent. Corp. Deriv. Litig., No. 096-320958-20 (Tex. Dist. Ct., Tarrant Cty.). We believe that these complaints are without merit and intend to defend these lawsuits vigorously. However, there can be no assurance regarding the ultimate outcome of these Wage and Hour Class Action Lawsuits ​ On March 8, 2016, certain plaintiffs filed a complaint against one of our subsidiaries in the Superior Court of Massachusetts, Suffolk County, on behalf of a purported class of current and former employees of Six Flags New England. The complaint alleges violations of Massachusetts law governing employee overtime and rest breaks, and seeks damages in the form of unpaid wages for overtime and meal breaks and related penalties. On November 12, 2020, the parties entered into a settlement agreement to resolve the lawsuit, for an immaterial amount, and final approval was granted by the court on March 31, 2021, and the case was dismissed on June 23, 2021. On April 20, 2018, a complaint was filed against Holdings and Six Flags Concord, LLC in the Superior Court of Solano County, California, on behalf of a purported class of current and former employees of Six Flags Discovery Kingdom. On June 15, 2018, an amended complaint was filed adding Park Management Corp. as a defendant. The amended complaint alleges violations of California law governing, among other things, employee overtime, meal and rest breaks, wage statements, and seeks damages in the form of unpaid wages and related penalties, and attorneys’ fees and costs. Following mediation on November 30, 2020, the parties agreed to a settlement in principle to resolve the lawsuit, for an immaterial amount. The settlement is subject to preliminary and final approval by the court On September 18, 2019, a complaint was filed against Magic Mountain LLC in the Superior Court of Los Angeles County, California, on behalf of a purported class of current and former employees of Six Flags Magic Mountain. An amended complaint was filed on November 24, 2019. On April 6, 2020, a copycat complaint was filed by the same law firm on behalf of a different named plaintiff alleging nearly identical causes of action. The complaints allege violations of California law governing payment of wages, wage statements, and background checks, and seek unpaid wages and statutory damages under California law as well as under the Private Attorneys General Act, and attorneys’ fees and costs. We intend to vigorously defend ourselves against these lawsuits. Since they are in an early stage, the outcome is currently not determinable and a reasonable estimate of loss or range of loss cannot be made. ​ On February 14, 2020, a complaint was filed against Magic Mountain, LLC in the Superior Court of Los Angeles County, California, on behalf of a purported class of current and former employees of Six Flags Magic Mountain. The complaint alleges one cause of action for failure to furnish accurate, itemized wage statements in violation of California labor law, and seeks statutory damages under California law as well as under the Private Attorneys General Act, and attorneys’ fees and costs. Following mediation on January 13, 2021, the parties agreed to a settlement in principle to resolve the lawsuit, for an immaterial amount. The settlement is subject to preliminary and final approval by the court. ​ On February 20, 2020, a complaint was filed against Park Management Corp. in the Superior Court of Solano County, California, on behalf of a purported class of current and former employees of Six Flags Discovery Kingdom. The complaint alleges violations of California law governing payment of wages, wage statements, and background checks, and seeks statutory damages under federal and California law and attorneys’ fees and costs. The claims related to wages and wage statements will be resolved under the settlement of the April 2018 litigation above. With respect to the remaining background check claims, we intend to vigorously defend ourselves against this litigation. Since this litigation is in an early stage, the outcome is currently not determinable and a reasonable estimate of loss or range of loss cannot be made. ​ COVID-19 Park Closure Lawsuits ​ Since COVID-19 began affecting the operations of our parks in mid-March 2020, three similar purported class action complaints were filed against Holdings or one of its subsidiaries in the United States District Court for the Central District of California on April 10, 2020, April 13, 2020, and April 21, 2020. These complaints allege that we, in violation of California law, charged members and season passholders while the parks were closed and did not provide refunds for the amounts charged. The complaints seek compensatory damages, punitive damages, restitution, and unspecified injunctive relief. On April 22, 2021, the parties entered into a settlement agreement to resolve the lawsuits, for an immaterial amount, which is subject to preliminary and final approval by the court

Business Segments

Business Segments	6 Months Ended
	Jul. 04, 2021
Business Segments
Business Segments	7. Business Segments We have only one reportable segment - parks. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) July 4, 2021 December 31, 2020 June 30, 2020 Domestic ​ $ 2,304,446 ​ $ 2,317,009 ​ $ 2,363,884 Foreign ​ ​ 132,116 ​ ​ 134,805 ​ ​ 124,715 Total ​ $ 2,436,562 ​ $ 2,451,814 ​ $ 2,488,599 ​ Revenues and loss before income taxes by domestic and foreign categories for the six months ended July 4, 2021, and June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic Foreign Total 2021 ​ (Amounts in thousands) Revenues ​ $ 521,346 ​ $ 20,465 ​ $ 541,811 Loss before income taxes ​ (1,753) ​ (5,296) ​ (7,049) 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 108,601 ​ $ 13,045 ​ $ 121,646 Loss before income taxes ​ (266,914) ​ (11,592) ​ (278,506) ​

Pension Benefits

Pension Benefits	6 Months Ended
	Jul. 04, 2021
Pension Benefits
Pension Benefits	8. Pension Benefits We froze our pension plan effective March 31, 2006, and effective February 16, 2009, the remaining participants in the pension plan no longer earned future benefits. The following summarizes our pension costs during the three and six months ended July 4, 2021, and June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended (Amounts in thousands) ​ July 4, 2021 ​ June 30, 2020 July 4, 2021 ​ June 30, 2020 Service cost ​ $ 275 ​ $ 325 ​ $ 550 ​ $ 650 Interest cost ​ 1,275 ​ 1,622 ​ 2,550 ​ 3,245 Expected return on plan assets ​ (3,069) ​ (3,279) ​ (6,138) ​ (6,558) Amortization of net actuarial loss ​ 340 ​ 258 ​ 680 ​ 515 Total net periodic benefit ​ $ (1,179) ​ $ (1,074) ​ $ (2,358) ​ $ (2,148) ​ The components of net periodic pension benefit other than the service cost component were included in "Other net periodic pension benefit" in the condensed consolidated statements of operations. Weighted-Average Assumptions Used To Determine Net Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ July 4, 2021 ​ June 30, 2020 ​ July 4, 2021 ​ June 30, 2020 ​ Discount rate 2.20 % 3.00 ​ 2.20 % 3.00 % Rate of compensation increase N/A N/A N/A N/A Expected return on plan assets 5.75 % 6.50 ​ 5.75 % 6.50 % ​ Employer Contributions During the six months ended June 30, 2020, we made pension contributions of $1.5 million. We did not make any pension contributions during the six month period ended July 4, 2021.

Stock Repurchase Plans and Shar

Stock Repurchase Plans and Shareholder Rights Plan	6 Months Ended
	Jul. 04, 2021
Stock Repurchase Plans and Shareholder Rights Plan
Stock Repurchase Plans and Shareholder Rights Plan	9. Stock Repurchase Plans and Shareholder Rights Plan On March 30, 2017, Holdings announced that its Board of Directors approved a stock repurchase plan that permits Holdings to repurchase an incremental $500.0 million in shares of Holdings’ common stock (the "March 2017 Stock Repurchase Plan"). As of July 4, 2021, Holdings had repurchased 4,607,000 shares at a cumulative cost of approximately $268.3 million and an average price per share of $58.25 under the March 2017 Stock Repurchase Plan, leaving approximately $231.7 million available for permitted repurchases. The amount of share repurchases is limited by the covenants in the Second Amended and Restated Credit Facility, the 2024 Notes, the 2025 Notes and the 2027 Notes. In April 2020 and August 2020, in connection with amendments to the Second Amended and Restated Credit Facility, we suspended dividend payments and stock repurchases due to the impact of the COVID-19 pandemic until the earlier of December 31, 2022, or such time as SFTP reduces the incremental revolving credit commitments by $131 million and begins using actual results to test compliance with the senior secured leverage financial maintenance covenant On March 31, 2020, Holdings entered into a Rights Agreement (the “Rights Agreement”). In accordance with the terms of the Rights Agreement, the rights issued thereunder expired on March 30, 2021

General - Basis of Presentati_2

General - Basis of Presentation (Policies)	6 Months Ended
	Jul. 04, 2021
General - Basis of Presentation
Consolidated U.S. GAAP Presentation	a. Consolidated U.S. GAAP Presentation Our accounting policies reflect industry practices and conform to U.S. GAAP. The unaudited condensed consolidated financial statements include our accounts and the accounts of our wholly owned subsidiaries. We also consolidate the partnerships that own Six Flags Over Texas ("SFOT") and Six Flags Over Georgia (including Six Flags White Water Atlanta) ("SFOG", and together with SFOT, the "Partnership Parks") as subsidiaries in our unaudited condensed consolidated financial statements, as we have determined that we have the power to direct the activities of the Partnership Parks that most significantly impact their economic performance and we have the obligation to absorb losses and receive benefits from the Partnership Parks that can be potentially significant to these entities. The equity interests owned by non-affiliated parties in the Partnership Parks are reflected in the accompanying unaudited condensed consolidated balance sheets as redeemable noncontrolling interests. See Note 6 for a description of the partnership agreements applicable to the Partnership Parks and Note 8 for further discussion on the non-affiliated parties’ share of the earnings of the Partnership Parks.
Income Taxes	b. Income Taxes We recorded a valuation allowance of $129.4 million, $128.2 million and $134.1 million as of July 4, 2021, December 31, 2020, and June 30, 2020, respectively, due to uncertainties related to our ability to use some of our deferred tax assets, primarily consisting of certain state net operating loss and other tax carryforwards, before they expire. The valuation allowance was based on our estimates of taxable income by jurisdiction in which we operate and the period over which our deferred tax assets were recoverable. Our projected taxable income over the foreseeable future indicates we will be able to use all of our federal net operating loss carryforwards before they expire. We classify interest and penalties attributable to income taxes as part of income tax expense. As of July 4, 2021, December 31, 2020, and June 30, 2020, we had no recorded amounts for accrued interest or penalties.
Goodwill and Intangibles	c. Goodwill and Intangibles Goodwill and intangible assets with indefinite lives are tested for impairment annually, or more frequently if events or circumstances indicate that the assets might be impaired. We identify our reporting unit and determine the carrying value of the reporting unit by assigning the assets and liabilities, including the existing goodwill and intangible assets, to the reporting unit. We then determine the fair value of the reporting unit and compare it to the carrying amount of the reporting unit. All of our parks are operated in a similar manner and have comparable characteristics in that they produce and distribute similar services and products using similar processes, have similar types of customers, are subject to similar regulations and exhibit similar economic characteristics. As such, we are a single reporting unit. As of July 4, 2021, the fair value of the single reporting unit exceeded our carrying amount. We have one reporting unit at the same level for which Holdings common stock is traded and we believe our market capitalization is the best indicator of our reporting unit’s fair value. At July 4, 2021, we determined that it is not more likely than not that the fair value of our intangible assets were less than their carrying amounts and there were no triggering events.
Long-Lived Assets	d. Long-Lived Assets We review long-lived assets, including finite-lived intangible assets subject to amortization, for impairment upon the occurrence of events or changes in circumstances that would indicate that the carrying value of the asset or group of assets may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of the asset or group of assets to the future net cash flows expected to be generated by the asset or group of assets. If such assets are not considered to be fully recoverable, any impairment to be recognized is measured by the amount by which the carrying amount of the asset or group of assets exceeds its respective fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. We determined that our long-lived assets were recoverable as of July 4, 2021.
Earnings Per Common Share	e. Earnings (loss) Per Common Share Earnings (loss) per common share for the three and six months ended July 4, 2021, and June 30, 2020, was calculated as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended (Amounts in thousands, except per share data) July 4, 2021 June 30, 2020 July 4, 2021 June 30, 2020 Net income (loss) attributable to Six Flags Entertainment Corporation $ 70,520 ​ $ (136,894) $ (25,319) ​ $ (221,440) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding - basic: ​ ​ 85,673 ​ ​ 84,704 ​ ​ 85,437 ​ ​ 84,680 Effect of dilutive stock options and restricted stock units ​ ​ 1,078 ​ ​ — ​ ​ — ​ ​ — Weighted-average common shares outstanding - diluted: ​ ​ 86,751 ​ ​ 84,704 ​ ​ 85,437 ​ ​ 84,680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings (loss) per share - basic: ​ $ 0.82 ​ $ (1.62) ​ $ (0.30) ​ $ (2.62) Earnings (loss) per share - diluted: ​ $ 0.81 ​ $ (1.62) ​ $ (0.30) ​ $ (2.62) ​ ​
Stock Benefit Plans	f. Stock Benefit Plans Pursuant to the Six Flags Entertainment Corporation Long-Term Incentive Plan (the "Long-Term Incentive Plan"), Holdings may grant stock options, stock appreciation rights, restricted stock, restricted stock units, unrestricted stock, deferred stock units, performance and cash-settled awards and dividend equivalent rights ("DERs") to select employees, officers, directors and consultants of Holdings and its affiliates. During the six months ended July 4, 2021, performance stock units were granted to key employees that will vest upon the achievement of specified EBITDA and revenue performance targets by 2023. The aggregate payout under these awards if the targets are achieved in 2023 would be 186,000 shares of Holdings’ common stock, but could be more or less depending on the level of achievement and timing thereof. There has been no stock-based compensation expense recorded for the performance stock units because, as of July 4, 2021, it is not deemed probable that we will achieve the specified performance targets in 2023. Based on the grant date fair value of these performance stock units as determined by the closing market price of Holdings’ common stock on the date of grant, the total unrecognized compensation cost related to these performance stock units at target achievement in 2023 is $9.3 million, which will be expensed over the service period if achievement of the performance conditions becomes probable. We will continue to evaluate the probability of achieving the performance conditions going forward, and will record the appropriate expense as necessary. ​ During the three and six months ended July 4, 2021, and June 30, 2020, stock-based compensation expense consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended (Amounts in thousands) July 4, 2021 June 30, 2020 July 4, 2021 June 30, 2020 Long-Term Incentive Plan ​ $ 2,785 ​ $ 6,015 ​ $ 9,347 ​ $ 10,220 Employee Stock Purchase Plan ​ 216 ​ 5 ​ 291 ​ 80 Total Stock-Based Compensation ​ $ 3,001 ​ $ 6,020 ​ $ 9,638 ​ $ 10,300 ​
Accounts Receivable, Net	g. Accounts Receivable, Net Accounts receivable are reported at net realizable value and consist primarily of amounts due from guests for the sale of group outings and multi-use admission products, such as season passes and the membership program. We are not exposed to a significant concentration of credit risk; however, based on the age of the receivables, our historical experience and other factors and assumptions we believe to be customary and reasonable, we record an allowance for doubtful accounts. As of July 4, 2021, December 31, 2020, and June 30, 2020, we have recorded an allowance for doubtful accounts of $29.8 million, $3.1 million and $6.4 million, respectively, which is primarily comprised of estimated payment defaults under our membership program. To the extent that payments under our membership program have not been recognized in revenue, the allowance for doubtful accounts recorded against our membership program is offset with a corresponding reduction in deferred revenue.
Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements	h. Recently Adopted Accounting Pronouncements In December 2019, FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“Update 2019-12”) i. Recent Accounting Pronouncements In August 2018, FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans: (“Update 2018-14”) In March 2020, FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting

General - Basis of Presentati_3

General - Basis of Presentation (Tables)	6 Months Ended
	Jul. 04, 2021
General - Basis of Presentation
Schedule of Transformation Costs Breakout by Quarter	​ ​ ​ ​ ​ ​ ​ ​ Transformation Costs Breakout by Quarter ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ July 4, 2021 ​ July 4, 2021 Amounts included in "Other expense, net" ​ ​ ​ ​ ​ ​ Consultant costs ​ $ 67 ​ $ 6,854 Technology modernization costs ​ ​ 976 ​ ​ 3,070 Employee termination costs ​ ​ 293 ​ ​ 1,108 Total transformation costs ​ $ 1,336 ​ $ 11,032
Schedule of earnings (loss) per common share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended (Amounts in thousands, except per share data) July 4, 2021 June 30, 2020 July 4, 2021 June 30, 2020 Net income (loss) attributable to Six Flags Entertainment Corporation $ 70,520 ​ $ (136,894) $ (25,319) ​ $ (221,440) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding - basic: ​ ​ 85,673 ​ ​ 84,704 ​ ​ 85,437 ​ ​ 84,680 Effect of dilutive stock options and restricted stock units ​ ​ 1,078 ​ ​ — ​ ​ — ​ ​ — Weighted-average common shares outstanding - diluted: ​ ​ 86,751 ​ ​ 84,704 ​ ​ 85,437 ​ ​ 84,680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings (loss) per share - basic: ​ $ 0.82 ​ $ (1.62) ​ $ (0.30) ​ $ (2.62) Earnings (loss) per share - diluted: ​ $ 0.81 ​ $ (1.62) ​ $ (0.30) ​ $ (2.62)
Schedule of stock-based compensation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended Six Months Ended (Amounts in thousands) July 4, 2021 June 30, 2020 July 4, 2021 June 30, 2020 Long-Term Incentive Plan ​ $ 2,785 ​ $ 6,015 ​ $ 9,347 ​ $ 10,220 Employee Stock Purchase Plan ​ 216 ​ 5 ​ 291 ​ 80 Total Stock-Based Compensation ​ $ 3,001 ​ $ 6,020 ​ $ 9,638 ​ $ 10,300

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jul. 04, 2021
Revenue
Schedule of revenues disaggregated by contract duration	The following tables present our revenues disaggregated by contract duration for the three and six month periods ended July 4, 2021, and June 30, 2020, respectively. Long-term and short-term contracts consist of our contracts with customers with terms greater than one year and less than or equal to one year, respectively. Sales and usage-based taxes are excluded from revenues. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended July 4, 2021 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ ​ ​ Park Food, ​ International ​ ​ ​ ​ ​ ​ ​ ​ Merchandise ​ Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 69,784 ​ $ 6,826 ​ $ 8,741 ​ $ 85,351 Short-term contracts and other (a) ​ 175,381 ​ 192,071 ​ 6,984 ​ 374,436 Total revenues ​ $ 245,165 ​ $ 198,897 ​ $ 15,725 ​ $ 459,787 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, 2020 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ (3,061) ​ $ (163) ​ $ 3,580 ​ $ 356 Short-term contracts and other (a) ​ 14,023 ​ 4,686 ​ 78 ​ 18,787 Total revenues ​ $ 10,962 ​ $ 4,523 ​ $ 3,658 ​ $ 19,143 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended July 4, 2021 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 76,794 ​ $ 7,823 ​ $ 12,904 ​ $ 97,521 Short-term contracts and other (a) ​ 212,705 ​ 222,298 ​ 9,287 ​ 444,290 Total revenues ​ $ 289,499 ​ $ 230,121 ​ $ 22,191 ​ $ 541,811 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, 2020 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 2,701 ​ $ 657 ​ $ 12,850 ​ $ 16,208 Short-term contracts and other (a) ​ 68,067 ​ 33,672 ​ 3,699 ​ 105,438 Total revenues ​ $ 70,768 ​ $ 34,329 ​ $ 16,549 ​ $ 121,646 (a) Other revenues primarily include sales of single-day tickets and short-term transactional sales for which we have the right to invoice. ​

Long-Term Indebtedness (Tables)

Long-Term Indebtedness (Tables)	6 Months Ended
	Jul. 04, 2021
Long-Term Indebtedness
Schedule of long-term debt	As of July 4, 2021, December 31, 2020 and June 30, 2020, the principal balance of our long-term debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) July 4, 2021 December 31, 2020 June 30, 2020 Second Amended and Restated Term Loan B $ 479,000 $ 479,000 $ 479,000 2024 Notes ​ 949,490 ​ 949,490 ​ 949,490 2025 Notes ​ ​ 725,000 ​ ​ 725,000 ​ ​ 725,000 2027 Notes ​ 500,000 ​ 500,000 ​ 500,000 Net discount ​ (3,803) ​ (4,357) ​ (4,910) Deferred financing costs ​ (23,605) ​ (26,492) ​ (28,651) Total long-term debt ​ $ 2,626,082 ​ $ 2,622,641 ​ $ 2,619,929 ​

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jul. 04, 2021
Accumulated Other Comprehensive Loss.
Schedule of components of AOCI	Changes in the composition of Accumulated Other Comprehensive Loss ("AOCI") during the six months ended July 4, 2021 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other ​ ​ Translation ​ Cash Flow ​ Defined Benefit ​ Income ​ Comprehensive (Amounts in thousands) Adjustment Hedges Plans Taxes Loss Balances at December 31, 2020 ​ $ (27,412) ​ $ (16,819) ​ $ (57,642) ​ $ 5,369 ​ $ (96,504) Net current period change ​ (462) ​ 2,529 ​ — ​ (613) ​ 1,454 Amounts reclassified from AOCI ​ — ​ 2,742 ​ 680 ​ (860) ​ 2,562 Balances at July 4, 2021 ​ $ (27,874) ​ $ (11,548) ​ $ (56,962) ​ $ 3,896 ​ $ (92,488)
Schedule of reclassifications out of accumulated other comprehensive income (loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of Reclassification from AOCI ​ Amount of Reclassification from AOCI ​ ​ ​ ​ Three Months Ended ​ Six Months Ended Component of AOCI Location of Reclassification into (Loss) Income ​ July 4, 2021 ​ June 30, 2020 July 4, 2021 ​ June 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of loss on interest rate hedge ​ Interest expense ​ $ 1,381 ​ $ 15,972 ​ $ 2,742 ​ $ 15,852 ​ ​ Income tax benefit ​ ​ (347) ​ ​ (3,980) ​ (689) ​ (3,950) ​ ​ Net of tax ​ $ 1,034 ​ $ 11,992 ​ $ 2,053 ​ $ 11,902 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of deferred actuarial loss and prior service cost Operating expenses ​ $ 340 ​ $ 258 ​ $ 680 ​ $ 515 ​ Income tax benefit ​ (86) ​ (64) ​ (171) ​ (128) ​ Net of tax ​ $ 254 ​ $ 194 ​ $ 509 ​ $ 387 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications ​ $ 1,288 ​ $ 12,186 ​ $ 2,562 ​ $ 12,289

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	6 Months Ended
	Jul. 04, 2021
Derivative Financial Instruments
Schedule of derivative assets at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Assets (Amounts in thousands) July 4, 2021 December 31, 2020 June 30, 2020 Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreements — current $ 833 ​ $ 877 ​ $ 655 Interest rate swap agreements — non-current ​ — ​ ​ 585 ​ ​ 677 ​ $ 833 $ 1,462 $ 1,332
Schedule of derivative liabilities at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Liabilities (Amounts in thousands) ​ July 4, 2021 December 31, 2020 June 30, 2020 Derivatives Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreements — current ​ $ (5,169) $ (5,251) $ (4,639) Interest rate swap agreements — non-current ​ ​ (6,434) ​ ​ (11,633) ​ ​ (13,693) Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreements — current ​ (4,830) ​ (4,875) ​ (4,345) Interest rate swap agreements — non-current ​ ​ (6,549) ​ ​ (9,032) ​ ​ (11,395) ​ ​ $ (22,982) $ (30,791) $ (34,072)
Schedule of derivative instruments recorded at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Asset Derivatives ​ ​ ​ ​ July 4, 2021 ​ December 31, 2020 ​ June 30, 2020 ​ Balance Sheet Classifications Fair Value Fair Value Fair Value Derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other current assets ​ $ 429 ​ $ 877 ​ $ 655 Interest rate contracts ​ Other long-term liabilities ​ ​ (72) ​ ​ 585 ​ ​ 677 Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ 357 ​ $ 1,462 ​ $ 1,332 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total asset derivatives ​ ​ ​ $ 357 ​ $ 1,462 ​ $ 1,332 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Liability Derivatives ​ ​ ​ ​ July 4, 2021 ​ December 31, 2020 ​ June 30, 2020 ​ Balance Sheet Classifications Fair Value Fair Value Fair Value Derivatives designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other accrued liabilities ​ $ (5,169) ​ $ (5,251) ​ $ (4,639) Interest rate contracts ​ Other long-term liabilities ​ ​ (6,434) ​ ​ (11,633) ​ ​ (13,693) Total derivatives designated as hedging instruments under ASC 815 ​ ​ ​ $ (11,603) ​ $ (16,884) ​ $ (18,332) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other current assets ​ $ 404 ​ $ — ​ $ — Interest rate contracts ​ Other accrued liabilities ​ ​ (4,830) ​ ​ (4,875) ​ ​ (4,345) Interest rate contracts ​ Other long-term liabilities ​ ​ (6,478) ​ ​ (9,032) ​ ​ (11,395) Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ (10,904) ​ $ (13,907) ​ $ (15,740) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liability derivatives ​ ​ ​ $ (22,507) ​ $ (30,791) ​ $ (34,072)
Schedule of gains and losses before taxes on derivatives designated as cash flow hedges	Three Months Ended July 4, 2021 and June 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss ​ Loss Reclassified from ​ ​ Recognized in AOCL ​ AOCL into Operations (Amounts in thousands) 2021 2020 2021 ​ 2020 Interest rate swap agreements ​ $ (1,354) $ (3,786) $ (1,381) $ (1,044) Total $ (1,354) $ (3,786) $ (1,381) $ (1,044) Six Months Ended July 4, 2021 and June 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (Loss) ​ Loss Reclassified from ​ ​ Recognized in AOCL ​ AOCL into Operations (Amounts in thousands) 2021 2020 2021 2020 Interest rate swap agreements ​ $ 2,529 $ (32,580) $ (2,742) $ (924) Total $ 2,529 $ (32,580) $ (2,742) $ (924)

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jul. 04, 2021
Commitments and Contingencies
Schedule of redeemable noncontrolling interests of the SFOT and SFOG partnerships	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) SFOT SFOG Total Balance at December 31, 2020 ​ $ 242,595 ​ $ 280,781 ​ $ 523,376 Purchase of redeemable units ​ (603) ​ (512) ​ (1,115) Fresh start accounting fair market value adjustment for purchased units ​ ​ (126) ​ ​ (68) ​ ​ (194) Net income attributable to noncontrolling interests ​ 10,433 ​ 10,450 ​ 20,883 Balance at July 4, 2021 ​ $ 252,299 ​ $ 290,651 ​ $ 542,950

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jul. 04, 2021
Business Segments
Schedule of information reflecting long-lived assets, revenues and income before income taxes by domestic and foreign categories	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) July 4, 2021 December 31, 2020 June 30, 2020 Domestic ​ $ 2,304,446 ​ $ 2,317,009 ​ $ 2,363,884 Foreign ​ ​ 132,116 ​ ​ 134,805 ​ ​ 124,715 Total ​ $ 2,436,562 ​ $ 2,451,814 ​ $ 2,488,599 ​ Revenues and loss before income taxes by domestic and foreign categories for the six months ended July 4, 2021, and June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic Foreign Total 2021 ​ (Amounts in thousands) Revenues ​ $ 521,346 ​ $ 20,465 ​ $ 541,811 Loss before income taxes ​ (1,753) ​ (5,296) ​ (7,049) 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 108,601 ​ $ 13,045 ​ $ 121,646 Loss before income taxes ​ (266,914) ​ (11,592) ​ (278,506)

Pension Benefits (Tables)

Pension Benefits (Tables)	6 Months Ended
	Jul. 04, 2021
Pension Benefits
Summary of pension costs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended (Amounts in thousands) ​ July 4, 2021 ​ June 30, 2020 July 4, 2021 ​ June 30, 2020 Service cost ​ $ 275 ​ $ 325 ​ $ 550 ​ $ 650 Interest cost ​ 1,275 ​ 1,622 ​ 2,550 ​ 3,245 Expected return on plan assets ​ (3,069) ​ (3,279) ​ (6,138) ​ (6,558) Amortization of net actuarial loss ​ 340 ​ 258 ​ 680 ​ 515 Total net periodic benefit ​ $ (1,179) ​ $ (1,074) ​ $ (2,358) ​ $ (2,148)
Schedule of weighted average assumptions used to determine benefit obligations and net cost	Weighted-Average Assumptions Used To Determine Net Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ July 4, 2021 ​ June 30, 2020 ​ July 4, 2021 ​ June 30, 2020 ​ Discount rate 2.20 % 3.00 ​ 2.20 % 3.00 % Rate of compensation increase N/A N/A N/A N/A Expected return on plan assets 5.75 % 6.50 ​ 5.75 % 6.50 %

General - Basis of Presentati_4

General - Basis of Presentation (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021USD ($)item	Jun. 30, 2020USD ($)	Jul. 04, 2021USD ($)item	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Apr. 30, 2020USD ($)	Mar. 31, 2020USD ($)
Summary of Significant Accounting Policies
Number of parks owned or operated | item	27		27
Number of reporting units | item			1
Transformation Initiative
Allowance for doubtful accounts	$ 29,800	$ 6,400	$ 29,800	$ 6,400	$ 3,100
Valuation allowance	129,400	134,100	129,400	134,100	128,200
Accrued interest and penalties, income taxes	0	0	0	0	$ 0
Other expense. net
Transformation Initiative
Consultant costs	67		6,854
Technology modernization costs	976		3,070
Employee termination costs	293		1,108
Total transformation costs	$ 1,336	$ 6,200	$ 11,032	$ 6,200
Second Amended and Restated Term Loan B
COVID 19 Considerations
Incremental borrowing capacity						$ 131,000
Maximum borrowing capacity						481,000	$ 350,000
Interest rate, stated percentage	3.00%		3.00%
Senior Unsecured 2025 Notes | Six Flags Theme Parks Inc.
COVID 19 Considerations
Debt instrument, face amount						$ 725,000
Interest rate, stated percentage						7.00%
United States
Summary of Significant Accounting Policies
Number of parks owned or operated | item	24		24
Mexico
Summary of Significant Accounting Policies
Number of parks owned or operated | item	2		2
Canada
Summary of Significant Accounting Policies
Number of parks owned or operated | item	1		1

General - Basis of Presentati_5

General - Basis of Presentation - Earnings (loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Calculation of earnings per common share
Net (loss) income attributable to Six Flags Entertainment Corporation common stockholders	$ 70,520	$ (136,894)	$ (25,319)	$ (221,440)
Weighted-average common shares outstanding:
Weighted-average common shares outstanding-basic (in shares)	85,673,000	84,704,000	85,437,000	84,680,000
Effect of dilutive stock options and restricted stock units (in shares)	1,078,000
Weighted-average common shares outstanding-diluted (in shares)	86,751,000	84,704,000	85,437,000	84,680,000
Earnings (loss) per share - basic (in dollars per share)	$ 0.82	$ (1.62)	$ (0.30)	$ (2.62)
Earnings (loss) per share - diluted (in dollars per share)	$ 0.81	$ (1.62)	$ (0.30)	$ (2.62)
Antidilutive options
Antidilutive stock options excluded from computation of diluted shares outstanding (in shares)	3,509,000	5,995,000	5,247,000	5,995,000

General - Basis of Presentati_6

General - Basis of Presentation - Stock Benefit Plans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Stock Benefit Plans
Stock-based compensation	$ 3,001,000	$ 6,020,000	$ 9,638,000	$ 10,300,000
Payment of cash dividends			$ 210,000	21,418,000
Performance awards
Stock Benefit Plans
Aggregate payout if targets achieved (in shares)	186,000		186,000
Unrecognized compensation cost	$ 9,300,000		$ 9,300,000
Stock-based compensation			0
Dividend Equivalent Rights
Stock Benefit Plans
Payment of cash dividends	200,000		200,000
Long Term Incentive Plan
Stock Benefit Plans
Stock-based compensation	2,785,000	6,015,000	9,347,000	10,220,000
Employee Stock Purchase Plan
Stock Benefit Plans
Stock-based compensation	$ 216,000	$ 5,000	$ 291,000	$ 80,000

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021USD ($)item	Jun. 30, 2020USD ($)	Jul. 04, 2021USD ($)item	Jun. 30, 2020USD ($)	Jan. 01, 2020USD ($)	Jan. 01, 2019USD ($)
Revenue
Revenues	$ 459,787	$ 19,143	$ 541,811	$ 121,646
Number of distinct obligations within international agreements | item	3		3
Long-term contracts
Revenue
Revenues	$ 85,351	356	$ 97,521	16,208
Contract with customer, liability					$ 77,600	$ 85,100
Contract with customer, liability, revenue recognized	26,600	4,000	35,000	19,600
Short-term contracts and other
Revenue
Revenues	374,436	18,787	444,290	105,438
Park admissions
Revenue
Revenues	245,165	10,962	289,499	70,768
Park admissions | Long-term contracts
Revenue
Revenues	69,784	(3,061)	76,794	2,701
Park admissions | Short-term contracts and other
Revenue
Revenues	175,381	14,023	212,705	68,067
Park food, merchandise and other
Revenue
Revenues	198,897	4,523	230,121	34,329
Park food, merchandise and other | Long-term contracts
Revenue
Revenues	6,826	(163)	7,823	657
Park food, merchandise and other | Short-term contracts and other
Revenue
Revenues	192,071	4,686	222,298	33,672
Sponsorship international agreements and accommodations
Revenue
Revenues	15,725	3,658	22,191	16,549
Sponsorship international agreements and accommodations | Long-term contracts
Revenue
Revenues	8,741	3,580	12,904	12,850
Sponsorship international agreements and accommodations | Short-term contracts and other
Revenue
Revenues	$ 6,984	$ 78	$ 9,287	$ 3,699

Revenue - Performance Obligatio

Revenue - Performance Obligations (Details) - Long-term contracts - USD ($) $ in Millions	Jul. 04, 2021	Jun. 30, 2020
Revenue
Performance obligation	$ 112.6	$ 79.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-05
Revenue
Performance obligation	$ 119.2
Expected timing of satisfaction, period	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-03
Revenue
Performance obligation	$ 18.1
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-02
Revenue
Performance obligation	$ 9.1
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue
Performance obligation	$ 2.5
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-12-30
Revenue
Performance obligation	$ 0.8
Expected timing of satisfaction, period	1 year

Long-Term Indebtedness - Additi

Long-Term Indebtedness - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Apr. 30, 2020	Jul. 04, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Aug. 31, 2019	Jun. 30, 2019	Apr. 30, 2017	Jun. 30, 2016
Interest Rate Swap
Summary of Long-term debt
Notional amount							$ 300,000
Interest Rate Swap Second Agreements
Summary of Long-term debt
Notional amount						$ 400,000
Amended And Restated Revolving Loan
Summary of Long-term debt
Maximum borrowing capacity		$ 481,000
Amended And Restated Term Loan B
Summary of Long-term debt
Maximum borrowing capacity		479,000
Second Amended and Restated Revolving Loan
Summary of Long-term debt
Long-term line of credit		0	$ 0	$ 0
Letters of credit outstanding, amount		$ 20,200	20,800	21,300
Commitment fee percentage		0.625%
Second Amended and Restated Term Loan B
Summary of Long-term debt
Maximum borrowing capacity	$ 481,000				$ 350,000
Long-term debt		$ 479,000	479,000	479,000
Interest rate, stated percentage		3.00%
Repayment of debt	315,000
Second Amended and Restated Term Loan B | LIBOR
Summary of Long-term debt
Basis spread on variable rate		1.75%
Senior Unsecured 2024 Notes
Summary of Long-term debt
Long-term debt		$ 949,490	949,490	949,490
Debt instrument, face amount									$ 300,000
Interest rate, stated percentage									4.875%
Periodic payment of interest		23,100
Senior Unsecured 2024 Notes Add-on
Summary of Long-term debt
Debt instrument, face amount								$ 700,000
Senior Unsecured 2025 Notes
Summary of Long-term debt
Long-term debt		725,000	725,000	725,000
Periodic payment of interest		25,400
Senior Unsecured 2025 Notes | Six Flags Theme Parks Inc.
Summary of Long-term debt
Debt instrument, face amount	$ 725,000
Interest rate, stated percentage	7.00%
Senior Unsecured 2027 Notes
Summary of Long-term debt
Long-term debt		500,000	$ 500,000	$ 500,000
Debt instrument, face amount								$ 500,000
Interest rate, stated percentage								5.50%
Periodic payment of interest		$ 13,800

Long-Term Indebtedness - Schedu

Long-Term Indebtedness - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020	Jun. 30, 2020
Summary of Long-term debt
Net discount	$ (3,803)	$ (4,357)	$ (4,910)
Deferred financing costs	(23,605)	(26,492)	(28,651)
Total long-term debt	2,626,082	2,622,641	2,619,929
Second Amended and Restated Term Loan B
Summary of Long-term debt
Long-term debt	479,000	479,000	479,000
Senior Unsecured 2024 Notes
Summary of Long-term debt
Long-term debt	949,490	949,490	949,490
Senior Unsecured 2025 Notes
Summary of Long-term debt
Long-term debt	725,000	725,000	725,000
Senior Unsecured 2027 Notes
Summary of Long-term debt
Long-term debt	500,000	500,000	500,000
Estimate of Fair Value Measurement
Summary of Long-term debt
Total long-term debt	$ 2,705,300	$ 2,693,300	$ 2,463,700

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Accumulated other comprehensive loss, net of tax
Beginning balance	$ (1,236,464)	$ (852,864)	$ (1,158,547)	$ (716,118)
Net current period change			1,454
Amounts reclassified from AOCI			2,562
Ending balance	(1,160,154)	(970,782)	(1,160,154)	(970,782)
Cumulative Translation Adjustment
Accumulated other comprehensive loss, net of tax
Beginning balance			(27,412)
Net current period change			(462)
Ending balance	(27,874)		(27,874)
Cash Flow Hedges
Accumulated other comprehensive loss, net of tax
Beginning balance			(16,819)
Net current period change			2,529
Amounts reclassified from AOCI			2,742
Ending balance	(11,548)		(11,548)
Defined Benefit Plans
Accumulated other comprehensive loss, net of tax
Beginning balance			(57,642)
Amounts reclassified from AOCI			680
Ending balance	(56,962)		(56,962)
Income Taxes
Accumulated other comprehensive loss, net of tax
Beginning balance			5,369
Net current period change			(613)
Amounts reclassified from AOCI			(860)
Ending balance	3,896		3,896
Accumulated other comprehensive loss
Accumulated other comprehensive loss, net of tax
Beginning balance	(94,295)	(110,423)	(96,504)	(74,710)
Ending balance	$ (92,488)	$ (99,421)	$ (92,488)	$ (99,421)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Reclassifications out of accumulated other comprehensive income (loss):
Income tax benefit	$ 29,257	$ (55,661)	$ (2,613)	$ (77,710)
Total reclassifications			(2,562)
Reclassification out of AOCI
Reclassifications out of accumulated other comprehensive income (loss):
Total reclassifications	1,288	12,186	2,562	12,289
Reclassification out of AOCI | Amortization of loss on interest rate hedge
Reclassifications out of accumulated other comprehensive income (loss):
Operating expenses	1,381	15,972	2,742	15,852
Income tax benefit	(347)	(3,980)	(689)	(3,950)
Total reclassifications	1,034	11,992	2,053	11,902
Reclassification out of AOCI | Amortization of deferred actuarial loss and prior service cost
Reclassifications out of accumulated other comprehensive income (loss):
Operating expenses	340	258	680	515
Income tax benefit	(86)	(64)	(171)	(128)
Total reclassifications	$ 254	$ 194	$ 509	$ 387

Derivative Financial Instrume_3

Derivative Financial Instruments - Derivative Instruments Recorded at Fair Value (Details) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020	Jun. 30, 2020
Derivative Financial Instruments
Derivative Assets	$ 357	$ 1,462	$ 1,332
Derivative Liabilities	(22,507)	(30,791)	(34,072)
Interest Rate Swap
Derivative Financial Instruments
Derivative Assets	833	1,462	1,332
Derivative Liabilities	(22,982)	(30,791)	(34,072)
Derivatives Designated as Cash Flow Hedges
Derivative Financial Instruments
Derivative Liabilities	(11,603)	(16,884)	(18,332)
Derivatives Designated as Cash Flow Hedges | Interest Rate Swap
Derivative Financial Instruments
Derivative Liabilities - Current	(5,169)	(5,251)	(4,639)
Derivative Liabilities - Noncurrent	(6,434)	(11,633)	(13,693)
Derivatives Not Designated as Hedging Instruments
Derivative Financial Instruments
Derivative Assets	357	1,462	1,332
Derivative Liabilities	(10,904)	(13,907)	(15,740)
Derivatives Not Designated as Hedging Instruments | Interest Rate Swap
Derivative Financial Instruments
Derivative Assets - Current	833	877	655
Derivative Assets - Noncurrent		585	677
Derivative Liabilities - Current	(4,830)	(4,875)	(4,345)
Derivative Liabilities - Noncurrent	$ (6,549)	$ (9,032)	$ (11,395)

Derivative Financial Instrume_4

Derivative Financial Instruments - Fair Value of Derivative Financial Instruments In Asset Position (Details) - USD ($) $ in Thousands	Jul. 04, 2021	Dec. 31, 2020	Jun. 30, 2020
Derivative Financial Instruments
Assets derivatives	$ 357	$ 1,462	$ 1,332
Liability derivatives	(22,507)	(30,791)	(34,072)
Derivatives Designated as Cash Flow Hedges
Derivative Financial Instruments
Liability derivatives	(11,603)	(16,884)	(18,332)
Derivatives Designated as Cash Flow Hedges | Interest rate Contracts | Other accrued liabilities
Derivative Financial Instruments
Liability derivatives	(5,169)	(5,251)	(4,639)
Derivatives Designated as Cash Flow Hedges | Interest rate Contracts | Other long-term liabilities
Derivative Financial Instruments
Liability derivatives	(6,434)	(11,633)	(13,693)
Derivatives Not Designated as Hedging Instruments
Derivative Financial Instruments
Assets derivatives	357	1,462	1,332
Liability derivatives	(10,904)	(13,907)	(15,740)
Derivatives Not Designated as Hedging Instruments | Interest rate Contracts | Other current assets
Derivative Financial Instruments
Assets derivatives	429	877	655
Liability derivatives	404
Derivatives Not Designated as Hedging Instruments | Interest rate Contracts | Other accrued liabilities
Derivative Financial Instruments
Liability derivatives	(4,830)	(4,875)	(4,345)
Derivatives Not Designated as Hedging Instruments | Interest rate Contracts | Other long-term liabilities
Derivative Financial Instruments
Assets derivatives	(72)	585	677
Liability derivatives	$ (6,478)	$ (9,032)	$ (11,395)

Derivative Financial Instrume_5

Derivative Financial Instruments - Gains and Losses before Taxes on Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Derivative Financial Instruments
Loss to be reclassified from AOCI to operations during the next twelve months	$ 5,100		$ 5,100
Derivatives Designated as Cash Flow Hedges
Derivative Financial Instruments
Loss recognized in AOCL	(1,354)	$ (3,786)	2,529	$ (32,580)
Loss Reclassified from AOCI into Operations (Effective Portion)	(1,381)	(1,044)	(2,742)	(924)
Derivatives Designated as Cash Flow Hedges | Interest Rate Swap
Derivative Financial Instruments
Loss recognized in AOCL	(1,354)	(3,786)	2,529	(32,580)
Loss Reclassified from AOCI into Operations (Effective Portion)	(1,381)	$ (1,044)	(2,742)	$ (924)
Derivatives Not Designated as Hedging Instruments
Derivative Financial Instruments
Loss recognized in Interest Expense	$ 100		$ 100

Commitments and Contingencies_2

Commitments and Contingencies (Details)

Apr. 21, 2020claim

Apr. 08, 2020claim

Jan. 07, 2016USD ($)

May 31, 2021USD ($)shares

Apr. 30, 2020lawsuit

Feb. 29, 2020claim

Jul. 04, 2021USD ($)multiple

Jun. 30, 2020USD ($)

Jan. 02, 2022USD ($)

Dec. 31, 2020USD ($)

Dec. 31, 2017claim

Apr. 07, 2017item

Details of commitments and contingencies

Redemption value of noncontrolling interests

$ 522,300,000

Additions to property and equipment

42,250,000

$ 75,623,000

Privacy Class Action Lawsuits | Pending Litigation

Details of commitments and contingencies

Number of claims filed | claim

4

Privacy Class Action Lawsuits | Pending Litigation | Minimum

Details of commitments and contingencies

Range of possible loss per aggrieved party

100

Privacy Class Action Lawsuits | Pending Litigation | Maximum

Details of commitments and contingencies

Range of possible loss per aggrieved party

1,000

Securities Class Action Lawsuits | Pending Litigation

Details of commitments and contingencies

Number of claims filed | claim

2

Stockholder Derivative Lawsuits | Pending Litigation

Details of commitments and contingencies

Number of claims filed | lawsuit

2

Number of claims consolidated | claim

3

COVID-19 Park Closure Lawsuits | Pending Litigation

Details of commitments and contingencies

Number of claims filed | claim

3

BIPA | Privacy Class Action Lawsuits | Pending Litigation

Details of commitments and contingencies

Number of questions certified for consideration by appellate court | item

2

BIPA | Privacy Class Action Lawsuits | Pending Litigation | Minimum

Details of commitments and contingencies

Range of possible loss per aggrieved party

$ 1,000

BIPA | Privacy Class Action Lawsuits | Pending Litigation | Maximum

Details of commitments and contingencies

Range of possible loss per aggrieved party

$ 5,000

Partnerships That Own Partnership Parks

Details of commitments and contingencies

Total loans receivable

$ 288,300,000

$ 239,300,000

$ 288,300,000

Six Flags over Georgia

Details of commitments and contingencies

Units purchased in partnership parks (in units) | shares

0.125

Purchase price of partnership units

$ 500,000

Remaining redeemable units (as a percent)

68.50%

Limited partner interests owned (as a percent)

31.50%

Six Flags over Texas

Details of commitments and contingencies

Units purchased in partnership parks (in units) | shares

0.25

Purchase price of partnership units

$ 600,000

Remaining redeemable units (as a percent)

46.00%

Limited partner interests owned (as a percent)

54.00%

Six Flags over Texas and Georgia

Details of commitments and contingencies

Rolling period for making minimum capital expenditure at each of the Partnership Parks

5 years

Percentage of capital expenditures to Partnership Parks' revenues

6.00%

Weighted average period of the park's EBITDA for calculation of value of purchase price

4 years

Additions to property and equipment

9,100,000

Cash generated from operating activities by partnerships, after deduction of capital expenditures and excluding the impact of short-term intercompany advances

$ 5,000,000

Six Flags over Georgia

Details of commitments and contingencies

Redemption value of noncontrolling interests

$ 280,300,000

Specified multiple for purchase price valuation (in multipliers) | multiple

8

Specified price for purchase of partnership parks

$ 409,700,000

Six Flags over Texas

Details of commitments and contingencies

Redemption value of noncontrolling interests

$ 242,000,000

Specified multiple for purchase price valuation (in multipliers) | multiple

8.5

Specified price for purchase of partnership parks

$ 527,400,000

Forecast | Six Flags over Texas and Georgia

Details of commitments and contingencies

Annual distributions by general partners to limited partners in partnership parks

$ 75,200,000

Share of Partnership Parks' annual distributions paid to Six Flags Entertainment Corporation

33,400,000

Additions to property and equipment

$ 12,000,000

Commitments and Contingencies-

Commitments and Contingencies- Redeemable noncontrolling interests (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020
Changes in redeemable noncontrolling interests
Redeemable noncontrolling interests, beginning balance	$ 523,376
Purchase of redeemable units	(1,115)	$ (4,976)
Fresh start accounting fair market value adjustment for purchased units	(194)
Net income attributable to noncontrolling interests	20,883
Redeemable noncontrolling interests, ending balance	542,950	$ 544,020
Redemption value of noncontrolling interests	522,300
Six Flags over Texas
Changes in redeemable noncontrolling interests
Redeemable noncontrolling interests, beginning balance	242,595
Purchase of redeemable units	(603)
Fresh start accounting fair market value adjustment for purchased units	(126)
Net income attributable to noncontrolling interests	10,433
Redeemable noncontrolling interests, ending balance	252,299
Redemption value of noncontrolling interests	242,000
Six Flags over Georgia
Changes in redeemable noncontrolling interests
Redeemable noncontrolling interests, beginning balance	280,781
Purchase of redeemable units	(512)
Fresh start accounting fair market value adjustment for purchased units	(68)
Net income attributable to noncontrolling interests	10,450
Redeemable noncontrolling interests, ending balance	290,651
Redemption value of noncontrolling interests	$ 280,300

Business Segments - Information

Business Segments - Information by Geographic Region (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021USD ($)item	Jun. 30, 2020USD ($)	Jul. 04, 2021USD ($)segmentitem	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Business segment information by geographical areas
Number of reportable segments | segment			1
Number of parks owned or operated | item	27		27
Long-lived assets	$ 2,436,562	$ 2,488,599	$ 2,436,562	$ 2,488,599	$ 2,451,814
Revenues	459,787	19,143	541,811	121,646
Income (loss) before income taxes	$ 120,660	(171,911)	$ (7,049)	(278,506)
Mexico
Business segment information by geographical areas
Number of parks owned or operated | item	2		2
Canada
Business segment information by geographical areas
Number of parks owned or operated | item	1		1
Domestic
Business segment information by geographical areas
Long-lived assets	$ 2,304,446	2,363,884	$ 2,304,446	2,363,884	2,317,009
Revenues			521,346	108,601
Income (loss) before income taxes			(1,753)	(266,914)
Foreign
Business segment information by geographical areas
Long-lived assets	$ 132,116	$ 124,715	132,116	124,715	$ 134,805
Revenues			20,465	13,045
Income (loss) before income taxes			$ (5,296)	$ (11,592)

Pension Benefits (Details)

Pension Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 30, 2020	Jul. 04, 2021	Jun. 30, 2020
Net periodic benefit cost:
Service cost	$ 275	$ 325	$ 550	$ 650
Interest cost	1,275	1,622	2,550	3,245
Expected return on plan assets	(3,069)	(3,279)	(6,138)	(6,558)
Amortization of net actuarial loss	340	258	680	515
Total net periodic benefit	$ (1,179)	$ (1,074)	$ (2,358)	$ (2,148)
Weighted average assumptions used to determine net cost
Discount rate	2.20%	3.00%	2.20%	3.00%
Expected return on plan assets	5.75%	6.50%	5.75%	6.50%
Employer contributions			$ 0	$ 1,500

Stock Repurchase Plans and Sh_2

Stock Repurchase Plans and Shareholder Rights Plan (Details) - USD ($) $ / shares in Units, $ in Millions	43 Months Ended
	Oct. 23, 2020	Mar. 31, 2021	Aug. 31, 2020	Mar. 30, 2017
Series B Junior Preferred Stock
Stock Repurchase Plans and Shareholder Rights Plan
Number of authorized shares of preferred stock (in shares)		200,000
March 2017 Stock Repurchase Plan
Stock Repurchase Plans and Shareholder Rights Plan
Amount authorized of shares to be repurchased under Stock Repurchase Program				$ 500
Total number of shares purchased (in shares)	4,607,000
Value of shares repurchased	$ 268.3
Shares acquired, average cost (in dollars per share)	$ 58.25
Permitted dollar value of repurchases remaining	$ 231.7
Amount of reduction in incremental revolving credit commitments required to allow repurchase of common stock			$ 131