Six Flags Entertainment 10-Q 28 Apr 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Apr. 04, 2021	Apr. 23, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Apr. 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		85,391,767
Entity Central Index Key	0000701374
Current Fiscal Year End Date	--01-02
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Current assets:
Cash and cash equivalents	$ 62,905	$ 157,760	$ 22,811
Accounts receivable, net	46,420	36,610	71,558
Inventories	39,057	39,191	42,397
Prepaid expenses and other current assets	69,166	73,179	79,496
Total current assets	217,548	306,740	216,262
Property and equipment, net:
Property and equipment, at cost	2,427,318	2,408,690	2,364,872
Accumulated depreciation	(1,182,641)	(1,157,403)	(1,073,198)
Total property and equipment, net	1,244,677	1,251,287	1,291,674
Other assets:
Right-of-use operating leases, net	194,768	196,711	194,519
Debt issuance costs	6,501	7,034	3,413
Deposits and other assets	6,661	7,103	10,452
Goodwill	659,618	659,618	659,618
Intangible assets, net of accumulated amortization of $244, $238 and $23,824 as of April 4, 2021, December 31, 2020 and March 31, 2020, respectively	344,192	344,198	344,611
Total other assets	1,211,740	1,214,664	1,212,613
Total assets	2,673,965	2,772,691	2,720,549
Current liabilities:
Accounts payable	31,771	26,582	48,994
Accrued compensation, payroll taxes and benefits	25,674	22,031	11,660
Accrued insurance reserves	27,568	31,060	33,223
Accrued interest payable	33,290	60,184	20,413
Other accrued liabilities	91,848	93,369	63,114
Deferred revenue	245,310	205,125	149,111
Short-term borrowings			40,000
Current portion of long-term debt			8,000
Short-term lease liabilities	10,547	14,054	10,490
Total current liabilities	466,008	452,405	385,005
Noncurrent liabilities:
Long-term debt	2,624,361	2,622,641	2,215,794
Long-term lease liabilities	190,362	187,432	186,062
Other long-term liabilities	35,337	43,553	43,238
Deferred income taxes	70,985	101,831	214,038
Total noncurrent liabilities	2,921,045	2,955,457	2,659,132
Total liabilities	3,387,053	3,407,862	3,044,137
Redeemable noncontrolling interests	523,376	523,376	529,276
Stockholders' deficit:
Preferred stock, $1.00 par value
Common stock, $0.025 par value, 280,000,000 shares authorized; 85,369,434, 85,075,901 and 84,666,505 shares issued and outstanding at April 4, 2021, December 31, 2020 and March 31, 2020, respectively	2,134	2,126	2,116
Capital in excess of par value	1,104,904	1,089,199	1,070,900
Accumulated deficit	(2,249,207)	(2,153,368)	(1,815,457)
Accumulated other comprehensive loss, net of tax	(94,295)	(96,504)	(110,423)
Total stockholders' deficit	(1,236,464)	(1,158,547)	(852,864)
Total liabilities and stockholders' deficit	$ 2,673,965	$ 2,772,691	$ 2,720,549

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Condensed Consolidated Balance Sheets
Accumulated amortization of intangible assets	$ 244	$ 238	$ 23,824
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)	85,369,434	85,075,901	84,666,505
Common stock, shares outstanding (in shares)	85,369,434	85,075,901	84,666,505

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Total revenues	$ 82,024	$ 102,503
Operating expenses (excluding depreciation and amortization shown separately below)	92,643	105,864
Selling, general and administrative expenses (including stock-based compensation of $6,637 and $4,280 in 2021 and 2020, respectively, and excluding depreciation and amortization shown separately below)	36,126	36,190
Costs of products sold	7,215	7,760
Other net periodic pension benefit	(1,643)	(996)
Depreciation	28,827	30,063
Amortization	6	601
Loss (gain) on disposal of assets	520	(120)
Interest expense	38,460	27,486
Interest income	(40)	(329)
Loss on debt extinguishment		1,019
Other expense, net	7,619	1,560
Loss before income taxes	(127,709)	(106,595)
Income tax benefit	(31,870)	(22,049)
Net loss	(95,839)	(84,546)
Net (loss) income attributable to Six Flags Entertainment Corporation	$ (95,839)	$ (84,546)
Weighted-average common shares outstanding - basic and diluted (in shares)	85,209	84,656
Net loss per average common share outstanding - basic and diluted (in dollars per share)	$ (1.12)	$ (1)
Cash dividends declared per common share		$ 0.25
Park admissions
Total revenues	$ 44,334	$ 59,806
Park food, merchandise and other
Total revenues	31,224	29,806
Sponsorship international agreements and accommodations
Total revenues	$ 6,466	$ 12,891

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Condensed Consolidated Statements of Operations
Stock-based compensation	$ 6,637	$ 4,280

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		3 Months Ended
		Apr. 04, 2021	Mar. 31, 2020
Condensed Consolidated Statements of Comprehensive Income (Loss)
Net loss		$ (95,839)	$ (84,546)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustment	[1]	(1,973)	(14,198)
Defined benefit retirement plan	[2]	255	193
Change in cash flow hedging	[3]	3,927	(21,708)
Other comprehensive income (loss), net of tax		2,209	(35,713)
Comprehensive loss		$ (93,630)	$ (120,259)
[1]	Foreign currency translation adjustment is presented net of tax benefit of $0.4 million for the three months ended April 4, 2021, and tax benefit of $3.8 million for the three months ended March 31, 2020
[2]	Defined benefit retirement plan is presented net of tax expense of $0.1 million for the three months ended April 4, 2021 and March 31, 2020.
[3]	Change in cash flow hedging is presented net of tax expense of $1.3 million for the three months ended April 4, 2021 and tax benefit of $7.2 million for the three months ended March 31, 2020, respectively.

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Condensed Consolidated Statements of Comprehensive Income (Loss)
Foreign currency translation adjustment, tax expense (benefit)	$ 0.4	$ (3.8)
Defined benefit retirement plan, tax expense (benefit)	0.1
Derivatives qualifying as hedges, tax expense (benefit)	$ 1.3	$ (7.2)

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	$ 1	421			422
Issuance of common stock (in shares)	32,788
Stock-based compensation		4,280			4,280
Dividends declared to common shareholders			(21,164)		(21,164)
Repurchase of common stock		(6)			(6)
Repurchase of common stock (in shares)	(155)
Employee stock purchase plan	$ (1)				(1)
Employee stock purchase plan (in shares)	27
Change in redemption value of partnership units		(18)			(18)
Net loss attributable to Six Flags Entertainment Corporation			(84,546)		(84,546)
Net other comprehensive loss, net of tax				(35,713)	(35,713)
Ending balance at Mar. 31, 2020	$ 2,116	1,070,900	(1,815,457)	(110,423)	(852,864)
Ending balance (in shares) at Mar. 31, 2020	84,666,505
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	$ 8	9,071			9,079
Issuance of common stock (in shares)	293,597
Stock-based compensation		6,637			6,637
Employee stock purchase plan		(3)			(3)
Employee stock purchase plan (in shares)	(64)
Net loss attributable to Six Flags Entertainment Corporation			(95,839)		(95,839)
Net other comprehensive loss, net of tax				2,209	2,209
Ending balance at Apr. 04, 2021	$ 2,134	$ 1,104,904	$ (2,249,207)	$ (94,295)	$ (1,236,464)
Ending balance (in shares) at Apr. 04, 2021	85,369,434

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Apr. 04, 2021	Mar. 31, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (95,839)	$ (84,546)
Adjustments to reconcile net loss to net cash used in and provided by operating activities:
Depreciation and amortization	28,833	30,664
Stock-based compensation	6,637	4,280
Interest accretion on notes payable	277	320
Loss on debt extinguishment		1,019
Amortization of debt issuance costs	1,978	856
Other, including loss (gain) on disposal of assets	(931)	1,546
Change in accounts receivable	(9,897)	35,159
Change in inventories, prepaid expenses and other current assets	3,907	(30,794)
Change in deposits and other assets	436	2,208
Change in ROU operating leases	2,113	2,437
Change in accounts payable, deferred revenue, accrued liabilities and other long-term liabilities	42,146	1,223
Change in operating lease liabilities	(1,182)	2,204
Change in accrued interest payable	(26,894)	(5,715)
Deferred income taxes	(31,982)	(21,248)
Net cash used in operating activities	(80,398)	(60,387)
Cash flows from investing activities:
Additions to property and equipment	(23,133)	(53,458)
Property insurance recoveries		2,042
Proceeds from sale of assets	33
Net cash used in investing activities	(23,100)	(51,416)
Cash flows from financing activities:
Repayment of borrowings	(2,000)	(117,510)
Proceeds from borrowings	2,000	105,000
Payment of cash dividends	(201)	(21,367)
Proceeds from issuance of common stock	9,078	421
Stock repurchases	(3)	(6)
Reduction in finance lease liability	(76)
Net cash provided by (used in) financing activities	8,798	(33,462)
Effect of exchange rate on cash	(155)	(6,103)
Net change in cash and cash equivalents	(94,855)	(151,368)
Cash and cash equivalents at beginning of period	157,760	174,179	$ 174,179
Cash and cash equivalents at end of period	62,905	22,811	$ 157,760
Supplemental cash flow information
Cash paid for interest	63,937	31,987
Cash paid for income taxes	$ 268	$ 1,959

General - Basis of Presentation

General - Basis of Presentation	3 Months Ended
	Apr. 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 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 April 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 will open 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. "Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations" contains a discussion of our results of operations and our financial position and should be read in conjunction with the unaudited condensed consolidated financial statements and notes. 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 for the three months ended April 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 temporarily suspended operations at all of our domestic theme parks and waterparks due to the COVID-19 pandemic. We have reopened or announced reopening dates for each of our parks with the exception of our park in Canada. Most parks that are currently operating have capacity and other operating limitations. 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. In response to the challenging environment, we focused on the following actions: ● Implemented immediate cost controls by right-sizing marketing and temporarily reducing salaries of all full-time employees by 25% ; ● Strengthened liquidity through expansion of our revolving credit facility, suspension of testing of certain maintenance covenants in our credit facility, issuance of senior secured notes, and suspension of dividend payments and stock repurchases; ● Enhanced financial flexibility by delaying and reducing capital expenses related to new rides and attractions; ● Developed measures to preserve our season pass holder and member bases; ● Opened parks as quickly as possible, while following governmental and public health guidelines; and ● Created new sources of revenue by introducing animal and holiday drive-thru experiences at many parks. ​ 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 quarter of 2021 for the parks that were open. 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 our open parks are required to close. 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 our senior secured leverage ratio financial maintenance covenant through the end of 2021. See Note 3, Long-Term Indebtedness, for more information on these transactions. In connection with the Second Amended and Restated Credit Agreement, we suspended dividend payments and stock repurchases 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 the senior secured leverage ratio financial maintenance covenant compliance. The COVID-19 pandemic continues to present material uncertainty and risk with respect to our performance and financial results, including around 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. 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 take to contain COVID-19 or treat its impact, among others. Our business and financial results could be materially and adversely impacted. Transformation Plan ​ ​ ​ ​ ​ Transformation Costs Breakout by Quarter ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ April 4, 2021 Amounts included in "Other expense, net" ​ ​ ​ Consultant costs ​ $ 6,787 Technology modernization costs ​ ​ 2,094 Employee termination costs ​ ​ 815 Total transformation costs ​ $ 9,696 ​ ​ 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 Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, including net operating loss and other tax carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. We recorded a valuation allowance of $129.4 million, $128.2 million and $132.2 million as of April 4, 2021, December 31, 2020 and March 31, 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. In determining the effective tax rate for interim periods, we consider the expected changes in our valuation allowance from current year originating or reversing timing differences between financial accounting and tax purposes and the taxable income or loss expected for the current year. For interim periods, we also account for the tax effect of significant non-recurring items in the period in which they occur as well as changes in the valuation allowance relating to a change in the assessment of the probability of utilization of the deferred income tax assets. Our liability for income taxes is finalized as auditable tax years pass their respective statutes of limitations in the various jurisdictions in which we are subject to tax. However, taxing authorities of these jurisdictions may audit prior years for which the statute of limitations is closed for the purpose of making an adjustment to our taxable income in a year for which the statute of limitations has not closed. Accordingly, taxing authorities of these jurisdictions may audit prior years of the Company and its predecessors for the purpose of adjusting net operating loss carryforwards to years for which the statute of limitations has not closed. We classify interest and penalties attributable to income taxes as part of income tax expense. As of April 4, 2021, December 31, 2020 and March 31, 2020, we had no recorded amounts for accrued interest or penalties. Because we do not permanently reinvest foreign earnings, United States deferred income taxes have been provided on unremitted foreign earnings to the extent that such foreign earnings are expected to be taxable upon repatriation. 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 April 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 April 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 April 4, 2021. e. Earnings Per Common Share Basic earnings per common share is computed by dividing net income attributable to Holdings’ common stockholders by the weighted average number of common shares outstanding for the period. Diluted earnings per common share is computed by dividing net income attributable to Holdings’ common stockholders by the weighted average number of common shares outstanding during the period, including the effect of all dilutive common stock equivalents using the treasury stock method. In periods for which there is a net loss, diluted loss per common share is equal to basic loss per common share, since the effect of including any common stock equivalents would be antidilutive. We incurred a net loss for the three months ended April 4, 2021 and March 31, 2020, therefore, diluted shares outstanding equaled basic shares outstanding for the purposes of determining loss per common share. The computation of diluted earnings per share excluded the effect of 6,199,000 and 5,907,000 antidilutive stock options for the three months ended April 4, 2021 and March 31, 2020, respectively. f . Derivative Instruments and Hedging Activities We recognize all derivatives as either assets or liabilities on the condensed consolidated balance sheet and measure those instruments at fair value. If certain conditions are met, a derivative may be specifically designated as a hedge for accounting purposes. The accounting for changes in the fair value of a derivative (e.g., gains and losses) depends on the intended use of the derivative and the resulting designation. We formally document all relationships between hedging instruments and hedged items, as well as our risk-management objective and our strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as cash flow hedges to forecasted transactions. We also assess, both at the hedge’s inception and on an ongoing basis throughout the contract term, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows of hedged items. Changes in the fair value of interest rate derivatives that are effective and that are designated and qualify as cash flow hedges are recorded in “Other comprehensive loss” until operations are affected by the variability in cash flows of the designated hedged item, at which point they are reclassified to “interest expense”. Changes in the fair value of derivatives that do not qualify for hedge accounting or that are de-designated are recorded in “Other expense, net” in the unaudited condensed consolidated statements of operations. g. Fair Value of Financial Instruments The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. We use a market approach for our recurring fair value measurements, and we endeavor to use the best information available. Accordingly, valuation techniques that maximize the use of observable impacts are favored. We present the estimated fair values and classifications of our financial instruments in accordance with U.S. GAAP . We use the following methods and assumptions to estimate the fair value of each class of financial instruments: ● The carrying values of cash and cash equivalents, accounts receivable, notes receivable, accounts payable and accrued liabilities approximate fair value because of the short maturity of these instruments. ● The measurement of the fair value of long-term debt is based on market prices that generally are observable for similar liabilities at commonly quoted intervals and is considered a Level 2 fair value measurement. ● The measurement of the fair value of derivative assets and liabilities is based on market prices that generally are observable for similar assets and liabilities at commonly quoted intervals and is considered a Level 2 fair value measurement. Derivative assets and liabilities that have maturity dates equal to or less than twelve months from the balance sheet date are included in prepaid and other current assets and other accrued liabilities, respectively. Derivative assets and 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. h. 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. We recognize the fair value of each grant as compensation expense on a straight-line basis over the vesting period using the graded vesting terms of the respective grant. The fair value of stock option grants is estimated using the Black-Scholes option pricing valuation model. The fair value of stock, restricted stock units and restricted stock awards is the quoted market price of Holdings’ common stock on the date of grant. During the three months ended April 4, 2021, performance stock units were granted to key employees that will vest upon the achievement of Adjusted EBITDA and Revenue performance targets by 2023. The aggregate payout under these awards if the targets are achieved in 2023 would be 186,000, 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 April 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 that 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 months ended April 4, 2021 and March 31, 2020, stock-based compensation expense consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) April 4, 2021 March 31, 2020 Long-Term Incentive Plan ​ $ 6,562 ​ $ 4,205 Employee Stock Purchase Plan ​ 75 ​ 75 Total Stock-Based Compensation ​ $ 6,637 ​ $ 4,280 ​ ​ i. Revenue Recognition We account for revenue from contracts with customers based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We recognize revenue upon admission into our parks, provision of our services, or when products are delivered to our guests. Revenues are presented in the accompanying condensed consolidated statements of operations net of sales taxes collected from our guests that are remitted or payable to government taxing authorities. For season passes, memberships in the initial twelve-month term and other multi-use admissions, we estimate a redemption rate based on historical experience and other factors and assumptions we believe to be customary and reasonable and recognize a pro-rata portion of the revenue as the guests visit our parks. Amounts owed or received for multi-use admissions in excess of redemptions are recognized in deferred revenue. In contrast to our season pass and other multi-use offerings (such as our all season dining pass program, which enables season passholders and members to eat meals and snacks any day they visit the park for one upfront payment) that expire at the end of each operating season, the membership program continues on a month-to-month basis after the initial twelve-month membership term and can be canceled any time after the initial term pursuant to the terms of the membership program. Guests enrolled in the membership program can visit our parks an unlimited number of times whenever the parks are open as long as the guest remains enrolled in the membership program. We review the estimated redemption rate on an ongoing basis and revise it as necessary throughout the year, including the impact of changes to our season pass and memberships described above. For any bundled products with multiple performance obligations, revenue is allocated using the retail price of each distinct performance obligation and products that are not sold on a stand-alone basis are treated as residual. ​ For active memberships after the initial twelve-month term, we recognize revenue monthly as payments are received, with the exception of those payments related to the parks that remain temporarily closed due to COVID-19. In connection with the temporary closure of our parks due to COVID-19, we added one additional month of membership privileges for every month a member paid but could not visit their home park. Any membership payments received while parks were temporarily closed due to the pandemic were deferred and will be recognized as revenue when these additional months are utilized at the end of the respective membership periods or when they exchange their additional months for a Six Flags gift card pursuant to our gift card exchange program, whichever is sooner. Season pass holders were granted an additional year of admission to the parks due to the COVID-19 pandemic. All 2020 passes now expire at the end of the 2021 season. ​ As of April 4, 2021, deferred revenue was primarily comprised of (i) unredeemed season pass and all-season dining pass revenue, (ii) unredeemed portions of the membership program, member dining program and member flash pass program that will primarily be recognized in 2021, (iii) pre-sold single day admissions revenue for the 2021 operating season and (iv) pre-sold single-day admissions revenue for the 2020 operating season which now expire at the end of the 2021 season. ​ Certain contracts with customers, primarily memberships, may include bundled products with multiple performance obligations. For such arrangements, we allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices based on the observable retail prices charged to customers and use residual for any products not sold on a stand-alone basis. We generally expense (i) sales commissions when incurred, and (ii) certain costs to obtain a contract where the amortization period would have been one year or less. These costs are recognized in "Selling, general and administrative expenses." We do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less or (ii) contracts for which we recognize revenue at the amount for which we have the right to invoice for services performed. For certain of our contracts that have an original expected length of one year or less, we use the practical expedient applicable to such contracts and do not consider the time value of money. We have entered into international agreements to assist a third party in the planning, design, development and operation of a Six Flags-branded park outside of North America. These agreements consist of a brand licensing agreement, project services agreement, and management services agreement. We treat these agreements as one contract because they were negotiated with a single commercial objective. We have identified three distinct promises within the agreement with the third-party partner as brand licensing, project services and management services. Each of these promises is its own performance obligation and distinct, as the third party could benefit from each service on its own with other readily available resources, and each service is separately identifiable from other services in the context of the contract. We recognize revenue under our international agreements over the relevant service period of each performance obligation based on its relative stand-alone selling price, as determined by our best estimate of selling price. We review the service period of each performance obligation on an ongoing basis and revise it as necessary throughout the year. Revisions to the relevant service periods of the performance obligations may result in revisions to revenue in future periods and are recognized in the period in which the change is identified. j. Leases We or certain of our subsidiaries are a lessee in various noncancelable operating and finance (formerly “capital”) leases, primarily for operating rights to amusement parks, land, office space, warehouses, office equipment and machinery. We account for leases in accordance with the Financial Accounting Standards Board (“FASB”) ASC 842, Leases For both our operating and finance leases, the lease liability is initially and subsequently measured at the present value of the unpaid lease payments at the lease commencement date. Key estimates and judgments include how we determine (i) the discount rate used to discount the unpaid lease payments to present value, (ii) the lease term and (iii) the lease payments. Topic 842 requires a lessee to discount its unpaid lease payments using the interest rate implicit in the lease or, if that rate cannot be readily determined, its incremental borrowing rate ("IBR"). Generally, we cannot determine the interest rate implicit in the lease and therefore we use the IBR as a discount rate for our leases. The IBR reflects the rate of interest we would pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. The lease term for all of our leases includes the noncancelable period of the lease plus any additional periods covered by an option to extend the lease that are reasonably certain to be executed by us. Lease payments included in the measurement of the lease liability comprise fixed payments owed over the lease term, variable lease payments that depend on an index or rate, and the exercise price of an option to purchase the underlying asset if it is reasonably certain that we will exercise the option. The ROU asset is initially measured at cost, which comprises the initial amount of lease liability adjusted for lease payments made at or before the lease commencement date, plus any initial direct costs incurred, less any lease incentives received. For our operating leases, the ROU asset is subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, and adjusted for any prepaid or accrued lease payments, less the unamortized balance of lease incentives received. Lease expense for lease payments is recognized on a straight-line basis over the term of the operating lease. Variable lease payments associated with our leases are recognized upon the occurrence of the event, activity, or circumstance in the lease agreement on which those payments are assessed. Variable lease payments for operating leases are presented as operating expense in our condensed consolidated statements of operations in the same line item as expense arising from fixed lease payments. Property taxes and insurance paid on behalf of our lessors is included within variable lease payments. Operating lease ROU assets net of accumulated amortization are presented as "Right-of-use operating leases, net" on the condensed consolidated balance sheets. The current portion of operating lease liabilities is presented as "Short-term lease liabilities" and the long-term portion is presented separately as "Long-term lease liabilities" on the condensed consolidated balance sheets. Finance lease ROU assets are presented within “Property and equipment, at cost” and the related lease amortization within “Accumulated depreciation” on our condensed consolidated balance sheets. The current portion of the finance lease liabilities is presented as “Short-term lease liabilities” and the long-term portion is presented separately as “Long-term lease liabilities” on our condensed consolidated balance sheets. We have elected not to recognize ROU assets and lease liabilities for short-term leases that have a lease term of 12 months or less. We recognize the lease payments associated with short-term leases as an expense on a straight-line basis over the lease term. Variable lease payments associated with short-term leases are recognized and presented in the same manner as for all other leases. The ROU assets for operating leases may be periodically reduced by impairment losses. We use the long-lived assets impairment guidance to determine whether an ROU asset is impaired and if so, the amount of the impairment loss to recognize. We monitor for events or changes in circumstances that require a reassessment of one of our leases. When a reassessment results in the remeasurement of a lease liability, an adjustment is made to the carrying amount of the corresponding ROU asset unless doing so would reduce the carrying amount of the ROU asset to an amount less than zero. In that case, the amount of the adjustment that would result in a negative ROU asset balance is recorded in our condensed consolidated statements of operations. k. 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 April 4, 2021, December 31, 2020 and March 31, 2020, we have recorded an allowance for doubtful accounts of $8.5 million, $3.1 million and $7.6 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. l. 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”), m. Recent Accounting Pronouncements Not Yet Adopted 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”)

Revenue

Revenue	3 Months Ended
	Apr. 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 months ended April 4, 2021 and March 31, 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 April 4, 2021 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ ​ ​ Park Food, ​ International ​ ​ ​ ​ ​ ​ ​ ​ Merchandise ​ Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 7,010 ​ $ 997 ​ $ 4,163 ​ $ 12,170 Short-term contracts and other (a) ​ 37,324 ​ 30,227 ​ 2,303 ​ 69,854 Total revenues ​ $ 44,334 ​ $ 31,224 ​ $ 6,466 ​ $ 82,024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 5,762 ​ $ 820 ​ $ 9,270 ​ $ 15,852 Short-term contracts and other (a) ​ 54,044 ​ 28,986 ​ 3,621 ​ 86,651 Total revenues ​ $ 59,806 ​ $ 29,806 ​ $ 12,891 ​ $ 102,503 (a) Other revenues primarily include sales of single-use 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. The transaction price for our long-term contracts is explicitly stated within the contracts. Our sponsorship contracts and international agreements may include estimated variable consideration such as penalties for delay in performance of contract terms, and certain volume-based discounts and rebates. We do not believe there will be significant changes to our estimates of variable consideration. Our brand licensing and management services performance agreements include royalty payments and management fees, respectively, based on gross sales from Six Flags-branded parks once opened. We have elected to apply the sales-based royalty exemption to the brand licensing performance obligation, and accordingly, do not estimate revenue attributable to the gross sales-based royalty. We have also elected to apply the direct allocation exemption to the management services performance obligation, and accordingly, do not estimate revenue attributable to the gross sales-based management fee. We recognize season pass revenue in "Park admissions" over the estimated redemption rate, as we believe this appropriately depicts the transfer of service to our customers. We estimate the redemption rate based on historical experience and other factors and assumptions that we believe to be customary and reasonable. We review the estimated redemption rate regularly, on an ongoing basis, and revise it as necessary throughout the year. Amounts received for multi-use admissions in excess of redemptions are recognized in "Deferred revenue." We recognize sponsorship and international agreements revenue over the term of the agreements using the passage of time as a measure of complete satisfaction of the performance obligations in "Sponsorship, international agreements and accommodations." Amounts received for unsatisfied sponsorship and international agreements performance obligations are recognized in "Deferred revenue." At January 1, 2021, $77.6 million of unearned revenue associated with outstanding long-term contracts was reported in "Deferred revenue," of which $8.4 million was recognized as revenue for long-term contracts during the three months ended April 4, 2021. As of April 4, 2021, the total unearned amount of revenue for remaining long-term contract performance obligations was $86.7 million. At January 1, 2020, $85.1 million of unearned revenue associated with outstanding long-term contracts was reported in "Deferred revenue," of which $10.2 million was recognized as revenue for long-term contracts during the three months ended March 31, 2020. As of March 31, 2020, the total unearned amount of revenue for remaining long-term contract performance obligations was $70.6 million. As of April 4, 2021, we expect to recognize estimated revenue for partially or wholly unsatisfied performance obligations on long-term contracts of approximately $100.8 million in the remainder of 2021 , $18.5 million in 2022 , $8.9 million in 2023 , $2.3 million in 2024 , and $0.8 million in 2025 and thereafter. Short-term Contracts and Other Our short-term contracts consist primarily of season passes and memberships with customers, certain sponsorship contracts and international agreements with third parties. We earn revenue from a customer’s purchase of our season pass and membership products, which entitles the customer to visit our parks, including certain waterparks, throughout the duration of the parks’ operating season for a fixed fee. Some membership products include other benefits and discounts for our guests during their visits. We earn sponsorship and international agreements revenue from contracts with third parties, pursuant to which we sell and advertise the third party’s products within our parks on a short-term basis that generally coincides with our annual operating season, and pursuant to certain activities in connection with our international agreements. The transaction price for our short-term contracts is explicitly stated within the contracts. We generally recognize revenue from short-term contracts over the passage of time, with the exception of season pass and membership revenues. We estimate the redemption rate based on historical experience and other factors and assumptions we believe to be customary and reasonable. We review the estimated redemption rate regularly and on an ongoing basis and revise it as necessary throughout the year. Amounts received for multi-use admissions in excess of redemptions are recognized in "Deferred revenue." Other revenues consist primarily of revenues from single-use tickets for entrance to our parks, in-park services (such as the sale of food and beverages, merchandise, games and attractions, standalone parking sales and other services inside our parks), accommodations revenue, and other miscellaneous products and services. Due to the short-term transactional nature of such purchases, we apply the practical expedient to recognize revenue for single-use ticket sales, in-park services, accommodations, and other miscellaneous services and goods for which we have the right to invoice. ​ Arrangements with Multiple Performance Obligations ​ Certain contracts with customers, primarily memberships, may include bundled products with multiple performance obligations. For such arrangements, we allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices based on the observable retail prices charged to customers and use residual for any products not sold on a stand-alone basis. We generally expense (i) sales commissions when incurred, and (ii) certain costs to obtain a contract where the amortization period would have been one year or less. These costs are recognized in "Selling, general and administrative expenses." We do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less or (ii) contracts for which we recognize revenue at the amount for which we have the right to invoice for services performed. For certain of our contracts that have an original expected length of one year or less, we use the practical expedient applicable to such contracts and do not consider the time value of money.

Long-Term Indebtedness

Long-Term Indebtedness	3 Months Ended
	Apr. 04, 2021
Long-Term Indebtedness
Long-Term Indebtedness	3. Long-Term Indebtedness Credit Facility As of April 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 discussed below. On October 18, 2019, we entered into an amendment to the Second Amended and Restated Credit Facility which reduced the overall borrowing rate on the Second Amended and Restated Term Loan B by 25 basis points by reducing the applicable margin from LIBOR plus 2.00% to LIBOR plus 1.75%. We recognized a loss on debt extinguishment of $0.3 million related to the transaction. On April 8, 2020, certain of our revolving credit lenders agreed to provide an incremental $131.0 million of revolving credit commitments to the Second Amended and Restated Revolving Loan, increasing the facility from $350.0 million to $481.0 million. On April 15, 2020, we received sufficient consents from the continuing lenders under the Second Amended and Restated Credit Facility (the “Credit Agreement Amendment”) substantially concurrently with the closing of the $725 million 2025 Notes discussed below which, among other things, (i) permitted the issuance of the 2025 Notes, including specifically, permitted the 2025 Notes to mature inside the Second Amended and Restated Term Loan B, (ii) suspended the testing of the senior secured leverage ratio financial maintenance covenant in the Second Amended and Restated Credit Facility through the end of 2020, (iii) re-established the financial maintenance covenant thereafter (provided that for the first, second, and third quarters of 2021 that such covenant is tested, we will be permitted to use the quarterly Borrower Consolidated Adjusted EBITDA (as defined in the Second Amended and Restated Credit Facility) from the second, third and fourth quarters of 2019 in lieu of the actual Borrower Consolidated Adjusted EBITDA for the corresponding quarters of 2020) and (iv) added a minimum liquidity covenant that will apply from the date of the Credit Agreement Amendment through December 31, 2021. The Credit Agreement Amendment became effective on April 22, 2020, after giving effect to the repayment of a portion of the Second Amended and Restated Term Loan B with a portion of the proceeds from the 2025 Notes. On April 22, 2020, SFTP completed the private sale of $725.0 million in aggregate principal amount of 7.00% senior secured notes due 2025. The net proceeds from this offering were used to repay the outstanding balance of the Second Amended and Restated Revolving Loan and $315.0 million of the Second Amended and Restated Term Loan B, and for general corporate and working capital purposes, including expenses relating to the offering. We recognized a loss on debt extinguishment of $5.1 million related to the transaction. On August 26, 2020, we entered into an amendment to the Second Amended and Restated Credit Facility which, among other things, (i) extended the previously effectuated suspension of the senior secured leverage ratio financial maintenance covenant in the Second Amended and Restated Credit Facility through the end of 2021, (ii) re-established the senior secured leverage ratio financial maintenance covenant thereafter (provided that for each quarter in 2022 (other than the fourth quarter) that the financial maintenance covenant is tested, SFTP will be permitted to use its quarterly Borrower Consolidated Adjusted EBITDA (as defined in the credit agreement governing the Second Amended and Restated Credit Facility) from the second, third, and fourth quarters of 2019 in lieu of the actual Borrower Consolidated Adjusted EBITDA for the corresponding quarters of 2021), (iii) reduced the commitment fee on the revolving credit facility, and (iv) extended the minimum liquidity covenant that will apply through December 31, 2022. The extension of the modifications to the financial covenant and other provisions in the Second Amended and Restated Credit Facility pursuant to this amendment will be in effect from the date of the amendment until the earlier of the delivery of the compliance certificate for the fourth quarter of 2022 and the date on which SFTP, in its sole discretion, elects to calculate its compliance with the financial maintenance covenant by using its actual Borrower Consolidated Adjusted EBITDA instead of the 2019 figures as outlined above. In addition, all of SFTP’s existing incremental revolving credit lenders agreed to extend the incremental $131 million revolving credit commitments to the Second Amended and Restated Revolving Loan by one year to December 31, 2022. As of April 4, 2021 and December 31, 2020, we had no amounts outstanding under the Second Amended and Restated Revolving Loan (excluding amounts reserved for letters of credit in the amount of $20.2 million and $21.0 million, respectively). As of March 31, 2020, we had $40.0 million outstanding under the Second Amended and Restated Revolving Loan (excluding amounts reserved for letters of credit in the amount of $21.3 million). 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 April 4, 2021, the Second Amended and Restated Revolving Loan unused commitment fee was 0.625%. The principal amount of the Second Amended and Restated Revolving Loan is due and payable on April 17, 2024. As of April 4, 2021 and December 31, 2020, $479.0 million was outstanding under the Second Amended and Restated Term Loan B, respectively. As of March 31, 2020, $794.0 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 the June 2019 Swap Agreements to mitigate the risk of an increase in the LIBOR interest rate in effect on the Second Amended and Restated Term Loan B. In August 2019, we entered into the August 2019 Swap Agreements to further mitigate the risk of an increase in the LIBOR interest rate in effect on the Second Amended and Restated Term Loan B. As of April 4, 2021, the applicable interest rate on the Second Amended and Restated Term Loan B was 3.00%. All remaining outstanding principal of the Second Amended and Restated Term Loan B is due and payable on April 17, 2026. Amounts outstanding under the Second Amended and Restated Credit Facility are guaranteed by Holdings, Six Flags Operations Inc. ("SFO") and certain of the domestic subsidiaries of SFTP (collectively, the "Loan Parties"). The Second Amended and Restated Credit Facility is secured by a first priority security interest in substantially all of the assets of the Loan Parties. The Second Amended and Restated Credit Facility agreement contains certain representations, warranties, affirmative covenants and a financial covenant (specifically, a maximum senior secured net leverage maintenance covenant). In addition, the Second Amended and Restated Credit Facility agreement contains restrictive covenants that, subject to certain exceptions, limit or restrict, among other things, the incurrence of indebtedness and liens, fundamental changes, restricted payments, investments, prepayments of certain indebtedness, transactions with affiliates, changes in fiscal periods, modifications of certain documents, and certain hedging agreements, subject, in each case, to certain carve-outs. 2024 Notes, 2025 Notes and 2027 Notes On June 16, 2016, Holdings issued $300.0 million of 4.875% senior unsecured notes due July 31, 2024 (the "2024 Notes"). We capitalized $4.7 million of debt issuance costs directly associated with the issuance of the 2024 Notes. We used approximately $150.0 million of the proceeds from the issuance of the 2024 Notes to reduce our borrowings under the 2015 Term Loan B. We used the remaining net proceeds of the sale of the 2024 Notes for general corporate and working capital purposes, which primarily included repurchases of our common stock. On April 13, 2017, Holdings issued an additional $700.0 million of 4.875% Senior Notes due July 31, 2024 (the "2024 Notes Add-on"). We capitalized $3.9 million of debt issuance costs directly associated with the issuance of the 2024 Notes Add-on. Interest payments of $24.4 million for the 2024 Notes and the 2024 Notes Add-on are due semi-annually on January 31 and July 31 of each year, with the exception of the first payment for the 2024 Notes on January 31, 2017, which was $9.1 million. On April 13, 2017, Holdings issued $500.0 million of 5.50% Senior Notes due April 15, 2027 (the "2027 Notes"). We capitalized $2.6 million of debt issuance costs directly associated with the issuance of the 2027 Notes. During March of 2020, we prepaid $50.5 million of the outstanding 2024 Notes principal reducing the outstanding amount to $949.5 million. We recognized a loss on debt extinguishment of $1.0 million. Interest payments of $23.1 million for the 2024 Notes and the 2024 Notes Add-on are due semi-annually on January 31 and July 31 of each year. On April 22, 2020, SFTP completed the private sale of $725.0 million in aggregate principal amount of 7.00% senior secured notes due 2025 (the “2025 Notes”). The net proceeds from this offering were used to repay the outstanding balance of the Second Amended and Restated Revolving Loan and $315.0 million of the Second Amended and Restated Term Loan B and for general corporate and working capital purposes, including expenses relating to the offering. In conjunction with the $315.0 million repayment of the Second Amended and Restated Term Loan B, certain of our hedging instruments that were entered into to mitigate the risk of an increase in the LIBOR interest rate and were de-designated. Consistent with policy, 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 designed to economically offset the impact of the de-designated swap agreements. Interest payments of $25.4 million are due semi-annually on January 1 and July 1 of each year, with the exception of January 1, 2021, which included the interest from April 22, 2020 through July 1, 2020 and totaled $35.1 million. The 2024 Notes, the 2024 Notes Add-on, the 2025 Notes and the 2027 Notes are guaranteed by the Loan Parties. The 2024 Notes, the 2024 Notes Add-on, the 2025 Notes and the 2027 Notes contain restrictive covenants that, subject to certain exceptions, limit or restrict, among other things, the ability of the Loan Parties to incur additional indebtedness, create liens, engage in mergers, consolidations and other fundamental changes, make investments, engage in transactions with affiliates, pay dividends and repurchase capital stock. The 2024 Notes, the 2024 Notes Add-on, 2025 Notes and the 2027 Notes contain certain events of default, including payment defaults, breaches of covenants and representations, cross defaults to other material indebtedness, judgment, and changes of control and bankruptcy events of default. Long-Term Indebtedness Summary As of April 4, 2021, December 31, 2020 and March 31, 2020, long-term debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) April 4, 2021 December 31, 2020 March 31, 2020 Second Amended and Restated Term Loan B $ 479,000 $ 479,000 $ 794,000 Second Amended and Restated Revolving Loan ​ ​ — ​ ​ — ​ ​ 40,000 2024 Notes ​ 949,490 ​ 949,490 ​ 949,490 2025 Notes ​ ​ 725,000 ​ ​ 725,000 ​ ​ — 2027 Notes ​ 500,000 ​ 500,000 ​ 500,000 Net discount ​ (4,080) ​ (4,357) ​ (6,002) Deferred financing costs ​ (25,049) ​ (26,492) ​ (13,694) Total debt ​ $ 2,624,361 ​ $ 2,622,641 ​ $ 2,263,794 Less current portion of long-term debt ​ — ​ — ​ (8,000) Less short-term borrowings ​ ​ — ​ ​ — ​ ​ (40,000) Total long-term debt ​ $ 2,624,361 ​ $ 2,622,641 ​ $ 2,215,794 ​ Fair-Value of Long-Term Indebtedness As of April 4, 2021, December 31, 2020 and March 31, 2020, the fair value of our long-term debt was $2,700.5 million, $2,693.3 million and $1,952.4 million, respectively.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Apr. 04, 2021
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss	4. Accumulated Other Comprehensive Loss Changes in the composition of Accumulated Other Comprehensive Loss ("AOCI") during the three months ended April 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 ​ (2,402) ​ 3,883 ​ — ​ (546) ​ 935 Amounts reclassified from AOCI ​ — ​ 1,361 ​ 340 ​ (427) ​ 1,274 Balances at April 4,2021 ​ $ (29,814) ​ $ (11,575) ​ $ (57,302) ​ $ 4,396 ​ $ (94,295) ​ The change in “Cumulative Translation Adjustment” was caused by the weakening of the United States Dollar against the Mexican Peso and the Canadian Dollar during the three months ended April 4, 2021. Our assets for our parks that we operate in Mexico and Canada are recorded in their local currencies and translated into United States Dollars on our condensed consolidated balance sheet. ​ The change in “Cash Flow Hedges” was caused by declining interest rates and continued projections of low interest rates in future interest rate forward curves. ​ The Company had the following reclassifications out of AOCI during the three months ended April 4, 2021 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of Reclassification from AOCI ​ ​ ​ ​ Three Months Ended Component of AOCI Location of Reclassification into (Loss) Income April 4, 2021 ​ March 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of loss on interest rate hedge ​ Interest Expense ​ $ 1,361 ​ $ (120) ​ ​ Income tax benefit ​ (342) ​ 30 ​ ​ Net of tax ​ $ 1,019 ​ $ (90) ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of deferred actuarial loss and prior service cost Operating expenses ​ $ 340 ​ $ 257 ​ Income tax expense ​ (85) ​ (64) ​ Net of tax ​ $ 255 ​ $ 193 ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications ​ $ 1,274 ​ $ 103 ​

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Apr. 04, 2021
Derivative Financial Instruments
Derivative Financial Instruments	5. Derivative Financial Instruments In June 2019, we entered into the June 2019 Swap Agreements with an aggregate notional amount of $300.0 million to mitigate the risk of an increase in the LIBOR interest rate in effect on the Second Amended and Restated Term Loan B. The term of the June 2019 Swap Agreements began in June 2019 and expires in June 2023. Upon execution, we designated and documented the June 2019 Swap Agreements as cash flow hedges. The June 2019 Swap Agreements serve as economic hedges and provide protection against rising interest rates. In August 2019, we entered into the August 2019 Swap Agreements with an aggregate notional amount of $400.0 million to mitigate the risk of an increase in the LIBOR interest rate in effect on the Second Amended and Restated Term Loan B. The term of the August 2019 Swap Agreements began in August 2019 and expires in August 2024. Upon execution, we designated and documented the August 2019 Swap Agreements as cash flow hedges. The August 2019 Swap Agreements serve as economic hedges and provide protection against rising interest rates. In March 2020, we executed a strategy common known as a “blend and extend” on $100.0 million of the June 2019 Swap Agreements that extended the length of one of the swap agreements through April 2026. We extended the existing pay-fixed swap rate over a longer period than its original term at a lower interest rate, while maintaining the same overall value of the swap. The remaining $200.0 million of the June 2019 Swap Agreements did not change. On April 22, 2020, we repaid $315.0 million of the Second Amended and Restated Term Loan B. In conjunction, the June 2019 Swap Agreements and the Modified June 2019 Swap Agreement were de-designated, since the hedged interest was no longer likely to occur due to the repayment of the debt. As a result, $14.9 million was reclassified from accumulated other comprehensive loss to interest expense in the condensed consolidated statement of operations. Consistent with company policy, 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 $300.0 million of notional amount counter-agreements (the “April 2020 Counter-agreements”) designed to economically offset the impact of the de-designated swap agreements. By utilizing a derivative instrument to hedge our exposure to LIBOR rate changes, we are exposed to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. To mitigate this risk, hedging instruments are placed with counterparties that we believe pose minimal credit risk. Market risk is the adverse effect on the value of a financial instrument that results from a change in interest rates, commodity prices or currency exchange rates. We manage the market risk associated with derivative instruments by establishing and monitoring parameters that limit the types and degree of market risk that we may undertake. We hold and issue derivative instruments for risk management purposes only and do not utilize derivatives for trading or speculative purposes. We record derivative instruments at fair value on our unaudited condensed consolidated balance sheets. When in qualifying relationships, the gains and losses on cash flow designated derivatives are deferred in AOCI and are reclassified to interest expense when the forecasted transaction takes place. The fair value of derivatives that are not designated as hedging instruments are recorded directly to “interest expense, net”. 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 April 4, 2021, December 31, 2020 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Asset Derivatives ​ ​ ​ ​ April 4, 2021 ​ December 31, 2020 ​ March 31, 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 ​ ​ 403 ​ ​ 877 ​ ​ — Interest rate contracts ​ Other long-term liabilities ​ ​ (157) ​ ​ 585 ​ ​ — Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ 246 ​ $ 1,462 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total asset derivatives ​ ​ ​ $ 246 ​ $ 1,462 ​ $ — ​ ​ The table below presents the fair value of our derivative financial instruments in a liability position as well as their classification on the unaudited condensed consolidated balance sheets as of April 4, 2021, December 31, 2020 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Liability Derivatives ​ ​ ​ ​ April 4, 2021 ​ December 31, 2020 ​ March 31, 2020 ​ Balance Sheet Classifications Fair Value Fair Value Fair Value Derivatives designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other accrued liabilities ​ ​ (5,139) ​ ​ (5,251) ​ ​ (7,689) Interest rate contracts ​ Other long-term liabilities ​ ​ (6,495) ​ ​ (11,633) ​ ​ (22,795) Total derivatives designated as hedging instruments under ASC 815 ​ ​ ​ $ (11,634) ​ $ (16,884) ​ $ (30,484) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other current assets ​ $ 398 ​ $ — ​ $ — Interest rate contracts ​ Other accrued liabilities ​ ​ (4,797) ​ ​ (4,875) ​ ​ — Interest rate contracts ​ Other long-term liabilities ​ ​ (7,353) ​ ​ (9,032) ​ ​ — Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ (11,752) ​ $ (13,907) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liability derivatives ​ ​ ​ $ (23,386) ​ $ (30,791) ​ $ (30,484) ​ Derivative assets recorded at fair value in our condensed consolidated balance sheets as of April 4, 2021, December 31, 2020 and March 31, 2020, respectively, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Assets (Amounts in thousands) April 4, 2021 December 31, 2020 March 31, 2020 Derivatives Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current $ — $ — $ — Interest Rate Swap Agreements — Noncurrent ​ — ​ ​ — ​ ​ — Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current 801 ​ 877 ​ — Interest Rate Swap Agreements — Noncurrent ​ — ​ ​ 585 ​ ​ — ​ $ 801 $ 1,462 $ — ​ Derivative liabilities recorded at fair value in our condensed consolidated balance sheets as of April 4, 2021, December 31, 2020 and March 31, 2020, respectively, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Liabilities (Amounts in thousands) ​ April 4, 2021 December 31, 2020 March 31, 2020 Derivatives Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current ​ $ (5,139) $ (5,251) $ (7,689) Interest Rate Swap Agreements — Noncurrent ​ ​ (6,495) ​ ​ (11,633) ​ ​ (22,795) Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current ​ (4,797) ​ (4,875) ​ — Interest Rate Swap Agreements — Noncurrent ​ ​ (7,510) ​ ​ (9,032) ​ ​ — ​ ​ $ (23,941) $ (30,791) $ (30,484) ​ Losses before taxes on derivatives not designated as a cash flow hedge of $0.1 million were presented in “Interest expense” in the condensed consolidated statement of operations for the three months ended April 4, 2021. ​ ​ 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 months ended April 4, 2021 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (Loss) ​ (Loss) Gain Reclassified from ​ ​ Recognized in AOCL ​ AOCL into Operations (Amounts in thousands) 2021 2020 2021 ​ 2020 Interest Rate Swap Agreements ​ $ 3,883 $ (28,794) $ (1,361) $ 120 Total $ 3,883 $ (28,794) $ (1,361) $ 120 ​ As of April 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 these derivatives.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Apr. 04, 2021
Commitments and Contingencies
Commitments and Contingencies	6. Commitments and Contingencies Partnership Parks On April 1, 1998, we acquired all of the capital stock of the former Six Flags Entertainment Corporation (a corporation that has been merged out of existence and that has always been a separate corporation from Holdings, "Former SFEC") for $976.0 million, paid in cash. In addition to our obligations under outstanding indebtedness and other securities issued or assumed in the Former SFEC acquisition, we also guaranteed certain contractual obligations relating to the Partnership Parks. Specifically, we 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 April 4, 2021, our share of the distribution will be approximately $33.3 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. Cash flow from operations at the Partnership Parks is used to satisfy these requirements first, before any funds are required from us. We also guaranteed the obligation of our subsidiaries to annually purchase all outstanding limited partnership units to the extent tendered by the unit holders (the "Partnership Park Put"). 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 during March of 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 April 4, 2021, is $409.7 million in the case of SFOG and $527.4 million in the case of SFOT. As of April 4, 2021, we owned approximately 31.4% and 53.9% 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. In 2027 and 2028, we will have the option to purchase all remaining units in the Georgia limited partner and the Texas limited partner, respectively, at a price based on the Specified Price, increased by a cost of living adjustment. As of the date of this quarterly report, we expect to purchase units from the Georgia and Texas partnerships for $1.0 million and $1.2 million, respectively, in May 2021 pursuant to the 2021 annual offer. 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 $523.4 million, representing approximately 68.6% of the outstanding units of SFOG and 46.1% of the outstanding units of SFOT. An additional $350.0 million of incremental borrowing is available under the Second Amended and Restated Credit Facility for future "put" obligations, if necessary. In connection with our acquisition of the Former SFEC, we entered into the Subordinated Indemnity Agreement with certain of the Company’s entities, Time Warner, and an affiliate of Time Warner (an indirect subsidiary of AT&T Inc. as a result of a merger in 2018), pursuant to which, among other things, we transferred to Time Warner (which has guaranteed all of our obligations under the Partnership Park arrangements) record title to the corporations that own the entities that have purchased and will purchase limited partnership units of the Partnership Parks, and we received an assignment from Time Warner of all cash flow received on such limited partnership units, and we otherwise control such entities. In addition, we issued preferred stock of the managing partner of the partnerships to Time Warner. In the event of a default by us under the Subordinated Indemnity Agreement or of our obligations to our partners in the Partnership Parks, these arrangements would permit Time Warner to take full control of both the entities that own the limited partnership units and the managing partner. If we satisfy all such obligations, Time Warner is required to transfer to us the entire equity interests of these entities. The 2018 merger of Time Warner and AT&T Inc. did not affect the Time Warner guarantee of our obligations under the Subordinated Indemnity Agreement. We incurred $9.1 million of capital expenditures at the Partnership Parks during the 2020 season and intend to incur approximately $11.0 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 April 4, 2021, December 31, 2020 and March 31, 2020, we had total loans receivable outstanding of $288.3 million, $288.3 million and $239.3 million, respectively, from the partnerships that own the Partnership Parks, primarily to fund the acquisition of Six Flags White Water Atlanta and to make capital improvements to the Partnership Parks and distributions to the limited partners in prior years. 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. We maintain multi-layered general liability policies that provide for excess liability coverage of up to $100.0 million per occurrence. For incidents arising on or after December 31, 2008, our self-insured retention is $2.0 million, followed by a $0.5 million deductible per occurrence applicable to all claims in the policy year for our domestic parks and our park in Canada and a nominal amount per occurrence for our parks in Mexico. Defense costs are in addition to these retentions. Our general liability policies cover the cost of punitive damages only in certain jurisdictions. Based upon reported claims and an estimate for incurred, but not reported claims, we accrue a liability for our self-insured contingencies. For workers’ compensation claims arising after November 15, 2003, our deductible is $0.75 million ($0.5 million deductible for the period from November 15, 2001 to November 15, 2003). We also maintain fire and extended coverage, business interruption, terrorism and other forms of insurance typical to businesses in our industry. Our all peril property coverage policies insure our real and personal properties (other than land) against physical damage resulting from a variety of hazards. Additionally, we maintain information security and privacy liability insurance in the amount of $10.0 million with a $0.25 million self-insured retention per event. 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. We intend to continue to vigorously defend ourselves against this litigation. The amount we have recorded is based on our estimate of the probable outcome of this litigation. ​ 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 preliminary approval was granted by the court on December 3, 2020 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. ​ 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. 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 lawsuits. ​ 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. 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 May 27, 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 seeks 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 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. ​ 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 September 9, 2020, the parties agreed to a settlement in principle to resolve the lawsuits, for an immaterial amount, which is subject to preliminary and final approval by the court

Leases

Leases	3 Months Ended
	Apr. 04, 2021
Operating Leases
Leases	7. Leases We have operating and finance leases for amusement parks, land, vehicles, machinery and certain equipment. Our leases have remaining lease terms of less than one year to 44 years, some of which include options to extend leases up to 20 years, and some of which include options to terminate the lease within one year. For our noncancelable operating leases with options to extend, because we may determine it is not reasonably certain we will exercise the option, the options are not considered in determining the lease term, and associated potential option payments are excluded from lease payments. Our leases generally do not include restrictive financial or other covenants. Payments due under the lease contracts include fixed payments and, for certain of our leases, variable payments. The components of lease cost for the three months ended April 4, 2021 and March 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) ​ April 4, 2021 ​ March 31, 2020 Finance lease expense ​ ​ ​ ​ ​ ​ Amortization of ROU assets ​ $ 157 ​ $ — Interest on lease liabilities ​ ​ 19 ​ ​ — Operating lease cost ​ ​ 6,130 ​ 6,263 Short-term lease cost ​ ​ 1,465 ​ ​ 1,602 Variable lease cost ​ ​ 1,338 ​ ​ 1,466 Total lease cost ​ $ 9,109 ​ $ 9,331 ​ Lease costs for the three months ended April 4, 2021 and March 31, 2020 included minimum rental payments under operating leases recognized on a straight-line basis over the term of the lease. ​ Other information related to leases for the three months ended April 4, 2021 and March 31, 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) ​ April 4, 2021 ​ March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows for operating leases ​ $ 5,208 ​ ​ $ 1,587 ​ Operating cash flows for finance leases ​ ​ 76 ​ ​ ​ — ​ Financing cash flows for finance leases ​ ​ 19 ​ ​ ​ — ​ Operating Leases ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for lease liabilities ​ ​ 79 ​ ​ 329 ​ Finance Leases ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for lease liabilities ​ ​ 439 ​ ​ ​ — ​ ​ Additional information related to our operating leases for the three months ended April 4, 2021 is as follows: ​ ​ ​ ​ ​ ​ Weighted-average remaining lease term (in years) ​ ​ 18.77 ​ Weighted-average discount rate ​ ​ 6.89 % ​ ​ ​ ​ ​ ​ ​ Weighted-average remaining lease term (in years) ​ ​ 3.43 ​ Weighted-average discount rate ​ ​ 3.83 % ​ The following tables set forth supplemental balance sheet information related to operating and finance leases as of April 4, 2021, December 31, 2020 and March 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) ​ April 4, 2021 ​ December 31, 2020 ​ March 31, 2020 Operating Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Right of use assets, net ​ $ 194,768 ​ $ 196,711 ​ $ 194,519 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term lease liabilities ​ ​ 10,037 ​ ​ 13,727 ​ ​ 10,490 Long-term lease liabilities ​ ​ 188,573 ​ ​ 185,823 ​ ​ 186,062 Total operating lease obligation ​ $ 198,610 ​ $ 199,550 ​ $ 196,552 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, at cost ​ $ 2,867 ​ $ 2,428 ​ $ — Accumulated depreciation ​ (405) ​ (248) ​ — Total property and equipment, net ​ 2,462 ​ 2,180 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term lease liabilities ​ $ 510 ​ $ 327 ​ $ — Long-term lease liabilities ​ ​ 1,789 ​ ​ 1,609 ​ ​ — Total finance lease obligation ​ $ 2,299 ​ $ 1,936 ​ $ — ​ Maturities of noncancelable operating and finance lease liabilities under Topic 842 as of April 4, 2021 are summarized in the table below: ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) As of April 4, 2021 ​ ​ Finance Leases ​ Operating Leases Remaining in 2021 ​ $ 398 ​ $ 21,685 2022 ​ 767 ​ 22,417 2023 ​ 769 ​ 21,955 2024 ​ 502 ​ 20,206 2025 ​ 24 ​ 18,127 Thereafter ​ — ​ 259,490 Total ​ $ 2,460 ​ $ 363,880 Less: present value discount ​ (161) ​ (165,270) Lease liability ​ $ 2,299 ​ $ 198,610 ​

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests	3 Months Ended
	Apr. 04, 2021
Redeemable Noncontrolling Interests
Redeemable Noncontrolling Interests	8. Redeemable Noncontrolling Interests 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 April 4, 2021, redeemable noncontrolling interests of the SFOT and SFOG partnerships was $242.6 million and $280.8 million, respectively which approximates redemption value.

Business Segments

Business Segments	3 Months Ended
	Apr. 04, 2021
Business Segments
Business Segments	9. Business Segments All of our owned or managed parks are located in the United States with the exception of two parks in Mexico and one park in Montreal, Canada. We also have revenue and expenses related to the development of a Six Flags-branded park outside of North America. ​ The following information reflects our long-lived assets (which consists of property and equipment, right-of-use operating leases and intangible assets) as of April 4, 2021, December 31, 2020 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) April 4, 2021 December 31, 2020 March 31, 2020 Domestic ​ $ 2,312,048 ​ $ 2,317,009 ​ $ 2,368,183 Foreign ​ ​ 131,207 ​ ​ 134,805 ​ ​ 122,239 Total ​ ​ 2,443,255 ​ ​ 2,451,814 ​ ​ 2,490,422 ​ Revenues and loss before income taxes by domestic and foreign categories as of or for the three months ended April 4, 2021 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic Foreign Total 2021 ​ (Amounts in thousands) Revenues ​ $ 78,673 ​ $ 3,351 ​ $ 82,024 Loss before income taxes ​ (121,192) ​ (6,517) ​ (127,709) 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 89,496 ​ $ 13,007 ​ $ 102,503 Loss before income taxes ​ (102,362) ​ (4,233) ​ (106,595) ​

Pension Benefits

Pension Benefits	3 Months Ended
	Apr. 04, 2021
Pension Benefits
Pension Benefits	10. Pension Benefits We froze our pension plan effective March 31, 2006, pursuant to which most participants no longer earned future pension benefits. 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 months ended April 4, 2021 and March 31, 2020, respectively: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) April 4, 2021 ​ March 31, 2020 Service cost ​ $ 275 ​ $ 325 Interest cost ​ 1,275 ​ 1,623 Expected return on plan assets ​ (3,069) ​ (3,279) Amortization of net actuarial loss ​ 340 ​ 257 Total net periodic benefit ​ $ (1,179) ​ $ (1,074) ​ 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 ​ ​ ​ April 4, 2021 ​ March 31, 2020 ​ Discount rate ​ 2.20 % 3.00 % Rate of compensation increase N/A N/A Expected return on plan assets ​ 5.75 % 6.50 % ​ Employer Contributions During the three month period ended March 31, 2020, we made pension contributions of $1.5 million. We did not make any pension contributions during the three month period ended April 4, 2021.

Stock Repurchase Plans and Shar

Stock Repurchase Plans and Shareholder Rights Plan	3 Months Ended
	Apr. 04, 2021
Stock Repurchase Plans and Shareholder Rights Plan
Stock Repurchase Plans and Shareholder Rights Plan	11. 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 April 23, 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 2024 Notes Add-on, the 2025 Notes and the 2027 Notes. In April 2020 and August 2020, in connection with amendments to the Second Amended and Restated Credit Agreement, 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 the senior secured leverage ratio financial maintenance covenant compliance. However, given the uncertainty associated with the ultimate impact of the COVID-19 pandemic on our business and operations, we may determine that it is prudent to continue these suspensions for a longer duration. Investors may have an expectation that we will resume our dividend at a certain time and at certain levels or repurchase shares available under Holdings’ repurchase program. The stock price of Holdings’ common stock could be adversely affected if our cash dividend rate or common stock repurchase activity differs from investors’ expectations. 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 ​

Subsequent Event

Subsequent Event	3 Months Ended
	Apr. 04, 2021
Subsequent Event
Subsequent Event	12. Subsequent Event In April 2021, we received $11.3 million pursuant to one of our terminated international development agreements in China. We currently do not anticipate any further payments related to any of the remaining terminated international development agreements.

General - Basis of Presentati_2

General - Basis of Presentation (Policies)	3 Months Ended
	Apr. 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 Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, including net operating loss and other tax carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. We recorded a valuation allowance of $129.4 million, $128.2 million and $132.2 million as of April 4, 2021, December 31, 2020 and March 31, 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. In determining the effective tax rate for interim periods, we consider the expected changes in our valuation allowance from current year originating or reversing timing differences between financial accounting and tax purposes and the taxable income or loss expected for the current year. For interim periods, we also account for the tax effect of significant non-recurring items in the period in which they occur as well as changes in the valuation allowance relating to a change in the assessment of the probability of utilization of the deferred income tax assets. Our liability for income taxes is finalized as auditable tax years pass their respective statutes of limitations in the various jurisdictions in which we are subject to tax. However, taxing authorities of these jurisdictions may audit prior years for which the statute of limitations is closed for the purpose of making an adjustment to our taxable income in a year for which the statute of limitations has not closed. Accordingly, taxing authorities of these jurisdictions may audit prior years of the Company and its predecessors for the purpose of adjusting net operating loss carryforwards to years for which the statute of limitations has not closed. We classify interest and penalties attributable to income taxes as part of income tax expense. As of April 4, 2021, December 31, 2020 and March 31, 2020, we had no recorded amounts for accrued interest or penalties. Because we do not permanently reinvest foreign earnings, United States deferred income taxes have been provided on unremitted foreign earnings to the extent that such foreign earnings are expected to be taxable upon repatriation.
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 April 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 April 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 April 4, 2021.
Earnings Per Common Share	e. Earnings Per Common Share Basic earnings per common share is computed by dividing net income attributable to Holdings’ common stockholders by the weighted average number of common shares outstanding for the period. Diluted earnings per common share is computed by dividing net income attributable to Holdings’ common stockholders by the weighted average number of common shares outstanding during the period, including the effect of all dilutive common stock equivalents using the treasury stock method. In periods for which there is a net loss, diluted loss per common share is equal to basic loss per common share, since the effect of including any common stock equivalents would be antidilutive. We incurred a net loss for the three months ended April 4, 2021 and March 31, 2020, therefore, diluted shares outstanding equaled basic shares outstanding for the purposes of determining loss per common share. The computation of diluted earnings per share excluded the effect of 6,199,000 and 5,907,000 antidilutive stock options for the three months ended April 4, 2021 and March 31, 2020, respectively.
Derivative Instruments and Hedging Activities	f . Derivative Instruments and Hedging Activities We recognize all derivatives as either assets or liabilities on the condensed consolidated balance sheet and measure those instruments at fair value. If certain conditions are met, a derivative may be specifically designated as a hedge for accounting purposes. The accounting for changes in the fair value of a derivative (e.g., gains and losses) depends on the intended use of the derivative and the resulting designation. We formally document all relationships between hedging instruments and hedged items, as well as our risk-management objective and our strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as cash flow hedges to forecasted transactions. We also assess, both at the hedge’s inception and on an ongoing basis throughout the contract term, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows of hedged items. Changes in the fair value of interest rate derivatives that are effective and that are designated and qualify as cash flow hedges are recorded in “Other comprehensive loss” until operations are affected by the variability in cash flows of the designated hedged item, at which point they are reclassified to “interest expense”. Changes in the fair value of derivatives that do not qualify for hedge accounting or that are de-designated are recorded in “Other expense, net” in the unaudited condensed consolidated statements of operations.
Fair Value of Financial Instruments	g. Fair Value of Financial Instruments The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. We use a market approach for our recurring fair value measurements, and we endeavor to use the best information available. Accordingly, valuation techniques that maximize the use of observable impacts are favored. We present the estimated fair values and classifications of our financial instruments in accordance with U.S. GAAP . We use the following methods and assumptions to estimate the fair value of each class of financial instruments: ● The carrying values of cash and cash equivalents, accounts receivable, notes receivable, accounts payable and accrued liabilities approximate fair value because of the short maturity of these instruments. ● The measurement of the fair value of long-term debt is based on market prices that generally are observable for similar liabilities at commonly quoted intervals and is considered a Level 2 fair value measurement. ● The measurement of the fair value of derivative assets and liabilities is based on market prices that generally are observable for similar assets and liabilities at commonly quoted intervals and is considered a Level 2 fair value measurement. Derivative assets and liabilities that have maturity dates equal to or less than twelve months from the balance sheet date are included in prepaid and other current assets and other accrued liabilities, respectively. Derivative assets and 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.
Stock Benefit Plans	h. 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. We recognize the fair value of each grant as compensation expense on a straight-line basis over the vesting period using the graded vesting terms of the respective grant. The fair value of stock option grants is estimated using the Black-Scholes option pricing valuation model. The fair value of stock, restricted stock units and restricted stock awards is the quoted market price of Holdings’ common stock on the date of grant. During the three months ended April 4, 2021, performance stock units were granted to key employees that will vest upon the achievement of Adjusted EBITDA and Revenue performance targets by 2023. The aggregate payout under these awards if the targets are achieved in 2023 would be 186,000, 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 April 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 that 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 months ended April 4, 2021 and March 31, 2020, stock-based compensation expense consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) April 4, 2021 March 31, 2020 Long-Term Incentive Plan ​ $ 6,562 ​ $ 4,205 Employee Stock Purchase Plan ​ 75 ​ 75 Total Stock-Based Compensation ​ $ 6,637 ​ $ 4,280 ​
Revenue Recognition	i. Revenue Recognition We account for revenue from contracts with customers based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We recognize revenue upon admission into our parks, provision of our services, or when products are delivered to our guests. Revenues are presented in the accompanying condensed consolidated statements of operations net of sales taxes collected from our guests that are remitted or payable to government taxing authorities. For season passes, memberships in the initial twelve-month term and other multi-use admissions, we estimate a redemption rate based on historical experience and other factors and assumptions we believe to be customary and reasonable and recognize a pro-rata portion of the revenue as the guests visit our parks. Amounts owed or received for multi-use admissions in excess of redemptions are recognized in deferred revenue. In contrast to our season pass and other multi-use offerings (such as our all season dining pass program, which enables season passholders and members to eat meals and snacks any day they visit the park for one upfront payment) that expire at the end of each operating season, the membership program continues on a month-to-month basis after the initial twelve-month membership term and can be canceled any time after the initial term pursuant to the terms of the membership program. Guests enrolled in the membership program can visit our parks an unlimited number of times whenever the parks are open as long as the guest remains enrolled in the membership program. We review the estimated redemption rate on an ongoing basis and revise it as necessary throughout the year, including the impact of changes to our season pass and memberships described above. For any bundled products with multiple performance obligations, revenue is allocated using the retail price of each distinct performance obligation and products that are not sold on a stand-alone basis are treated as residual. ​ For active memberships after the initial twelve-month term, we recognize revenue monthly as payments are received, with the exception of those payments related to the parks that remain temporarily closed due to COVID-19. In connection with the temporary closure of our parks due to COVID-19, we added one additional month of membership privileges for every month a member paid but could not visit their home park. Any membership payments received while parks were temporarily closed due to the pandemic were deferred and will be recognized as revenue when these additional months are utilized at the end of the respective membership periods or when they exchange their additional months for a Six Flags gift card pursuant to our gift card exchange program, whichever is sooner. Season pass holders were granted an additional year of admission to the parks due to the COVID-19 pandemic. All 2020 passes now expire at the end of the 2021 season. ​ As of April 4, 2021, deferred revenue was primarily comprised of (i) unredeemed season pass and all-season dining pass revenue, (ii) unredeemed portions of the membership program, member dining program and member flash pass program that will primarily be recognized in 2021, (iii) pre-sold single day admissions revenue for the 2021 operating season and (iv) pre-sold single-day admissions revenue for the 2020 operating season which now expire at the end of the 2021 season. ​ Certain contracts with customers, primarily memberships, may include bundled products with multiple performance obligations. For such arrangements, we allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices based on the observable retail prices charged to customers and use residual for any products not sold on a stand-alone basis. We generally expense (i) sales commissions when incurred, and (ii) certain costs to obtain a contract where the amortization period would have been one year or less. These costs are recognized in "Selling, general and administrative expenses." We do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less or (ii) contracts for which we recognize revenue at the amount for which we have the right to invoice for services performed. For certain of our contracts that have an original expected length of one year or less, we use the practical expedient applicable to such contracts and do not consider the time value of money. We have entered into international agreements to assist a third party in the planning, design, development and operation of a Six Flags-branded park outside of North America. These agreements consist of a brand licensing agreement, project services agreement, and management services agreement. We treat these agreements as one contract because they were negotiated with a single commercial objective. We have identified three distinct promises within the agreement with the third-party partner as brand licensing, project services and management services. Each of these promises is its own performance obligation and distinct, as the third party could benefit from each service on its own with other readily available resources, and each service is separately identifiable from other services in the context of the contract. We recognize revenue under our international agreements over the relevant service period of each performance obligation based on its relative stand-alone selling price, as determined by our best estimate of selling price. We review the service period of each performance obligation on an ongoing basis and revise it as necessary throughout the year. Revisions to the relevant service periods of the performance obligations may result in revisions to revenue in future periods and are recognized in the period in which the change is identified.
Leases	j. Leases We or certain of our subsidiaries are a lessee in various noncancelable operating and finance (formerly “capital”) leases, primarily for operating rights to amusement parks, land, office space, warehouses, office equipment and machinery. We account for leases in accordance with the Financial Accounting Standards Board (“FASB”) ASC 842, Leases For both our operating and finance leases, the lease liability is initially and subsequently measured at the present value of the unpaid lease payments at the lease commencement date. Key estimates and judgments include how we determine (i) the discount rate used to discount the unpaid lease payments to present value, (ii) the lease term and (iii) the lease payments. Topic 842 requires a lessee to discount its unpaid lease payments using the interest rate implicit in the lease or, if that rate cannot be readily determined, its incremental borrowing rate ("IBR"). Generally, we cannot determine the interest rate implicit in the lease and therefore we use the IBR as a discount rate for our leases. The IBR reflects the rate of interest we would pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. The lease term for all of our leases includes the noncancelable period of the lease plus any additional periods covered by an option to extend the lease that are reasonably certain to be executed by us. Lease payments included in the measurement of the lease liability comprise fixed payments owed over the lease term, variable lease payments that depend on an index or rate, and the exercise price of an option to purchase the underlying asset if it is reasonably certain that we will exercise the option. The ROU asset is initially measured at cost, which comprises the initial amount of lease liability adjusted for lease payments made at or before the lease commencement date, plus any initial direct costs incurred, less any lease incentives received. For our operating leases, the ROU asset is subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, and adjusted for any prepaid or accrued lease payments, less the unamortized balance of lease incentives received. Lease expense for lease payments is recognized on a straight-line basis over the term of the operating lease. Variable lease payments associated with our leases are recognized upon the occurrence of the event, activity, or circumstance in the lease agreement on which those payments are assessed. Variable lease payments for operating leases are presented as operating expense in our condensed consolidated statements of operations in the same line item as expense arising from fixed lease payments. Property taxes and insurance paid on behalf of our lessors is included within variable lease payments. Operating lease ROU assets net of accumulated amortization are presented as "Right-of-use operating leases, net" on the condensed consolidated balance sheets. The current portion of operating lease liabilities is presented as "Short-term lease liabilities" and the long-term portion is presented separately as "Long-term lease liabilities" on the condensed consolidated balance sheets. Finance lease ROU assets are presented within “Property and equipment, at cost” and the related lease amortization within “Accumulated depreciation” on our condensed consolidated balance sheets. The current portion of the finance lease liabilities is presented as “Short-term lease liabilities” and the long-term portion is presented separately as “Long-term lease liabilities” on our condensed consolidated balance sheets. We have elected not to recognize ROU assets and lease liabilities for short-term leases that have a lease term of 12 months or less. We recognize the lease payments associated with short-term leases as an expense on a straight-line basis over the lease term. Variable lease payments associated with short-term leases are recognized and presented in the same manner as for all other leases. The ROU assets for operating leases may be periodically reduced by impairment losses. We use the long-lived assets impairment guidance to determine whether an ROU asset is impaired and if so, the amount of the impairment loss to recognize. We monitor for events or changes in circumstances that require a reassessment of one of our leases. When a reassessment results in the remeasurement of a lease liability, an adjustment is made to the carrying amount of the corresponding ROU asset unless doing so would reduce the carrying amount of the ROU asset to an amount less than zero. In that case, the amount of the adjustment that would result in a negative ROU asset balance is recorded in our condensed consolidated statements of operations.
Accounts Receivable, Net	k. 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 April 4, 2021, December 31, 2020 and March 31, 2020, we have recorded an allowance for doubtful accounts of $8.5 million, $3.1 million and $7.6 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	l. 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”), m. Recent Accounting Pronouncements Not Yet Adopted 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”)

General - Basis of Presentati_3

General - Basis of Presentation (Tables)	3 Months Ended
	Apr. 04, 2021
General - Basis of Presentation
Schedule of Transformation Costs Breakout by Quarter	​ ​ ​ ​ ​ Transformation Costs Breakout by Quarter ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ April 4, 2021 Amounts included in "Other expense, net" ​ ​ ​ Consultant costs ​ $ 6,787 Technology modernization costs ​ ​ 2,094 Employee termination costs ​ ​ 815 Total transformation costs ​ $ 9,696
Schedule of stock-based compensation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) April 4, 2021 March 31, 2020 Long-Term Incentive Plan ​ $ 6,562 ​ $ 4,205 Employee Stock Purchase Plan ​ 75 ​ 75 Total Stock-Based Compensation ​ $ 6,637 ​ $ 4,280

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Apr. 04, 2021
Revenue
Schedule of revenues disaggregated by contract duration	The following tables present our revenues disaggregated by contract duration for the three months ended April 4, 2021 and March 31, 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 April 4, 2021 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ ​ ​ Park Food, ​ International ​ ​ ​ ​ ​ ​ ​ ​ Merchandise ​ Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 7,010 ​ $ 997 ​ $ 4,163 ​ $ 12,170 Short-term contracts and other (a) ​ 37,324 ​ 30,227 ​ 2,303 ​ 69,854 Total revenues ​ $ 44,334 ​ $ 31,224 ​ $ 6,466 ​ $ 82,024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ ​ ​ ​ ​ Sponsorship, ​ ​ ​ ​ ​ ​ Park Food, International ​ ​ ​ ​ ​ ​ ​ Merchandise Agreements and ​ ​ ​ (Amounts in thousands) Park Admissions and Other Accommodations Consolidated Long-term contracts ​ $ 5,762 ​ $ 820 ​ $ 9,270 ​ $ 15,852 Short-term contracts and other (a) ​ 54,044 ​ 28,986 ​ 3,621 ​ 86,651 Total revenues ​ $ 59,806 ​ $ 29,806 ​ $ 12,891 ​ $ 102,503 (a) Other revenues primarily include sales of single-use tickets and short-term transactional sales for which we have the right to invoice. ​

Long-Term Indebtedness (Tables)

Long-Term Indebtedness (Tables)	3 Months Ended
	Apr. 04, 2021
Long-Term Indebtedness
Schedule of long-term debt	As of April 4, 2021, December 31, 2020 and March 31, 2020, long-term debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) April 4, 2021 December 31, 2020 March 31, 2020 Second Amended and Restated Term Loan B $ 479,000 $ 479,000 $ 794,000 Second Amended and Restated Revolving Loan ​ ​ — ​ ​ — ​ ​ 40,000 2024 Notes ​ 949,490 ​ 949,490 ​ 949,490 2025 Notes ​ ​ 725,000 ​ ​ 725,000 ​ ​ — 2027 Notes ​ 500,000 ​ 500,000 ​ 500,000 Net discount ​ (4,080) ​ (4,357) ​ (6,002) Deferred financing costs ​ (25,049) ​ (26,492) ​ (13,694) Total debt ​ $ 2,624,361 ​ $ 2,622,641 ​ $ 2,263,794 Less current portion of long-term debt ​ — ​ — ​ (8,000) Less short-term borrowings ​ ​ — ​ ​ — ​ ​ (40,000) Total long-term debt ​ $ 2,624,361 ​ $ 2,622,641 ​ $ 2,215,794 ​

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Apr. 04, 2021
Accumulated Other Comprehensive Loss
Schedule of components of AOCI	Changes in the composition of Accumulated Other Comprehensive Loss ("AOCI") during the three months ended April 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 ​ (2,402) ​ 3,883 ​ — ​ (546) ​ 935 Amounts reclassified from AOCI ​ — ​ 1,361 ​ 340 ​ (427) ​ 1,274 Balances at April 4,2021 ​ $ (29,814) ​ $ (11,575) ​ $ (57,302) ​ $ 4,396 ​ $ (94,295)
Schedule of reclassifications out of accumulated other comprehensive income (loss)	The Company had the following reclassifications out of AOCI during the three months ended April 4, 2021 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of Reclassification from AOCI ​ ​ ​ ​ Three Months Ended Component of AOCI Location of Reclassification into (Loss) Income April 4, 2021 ​ March 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of loss on interest rate hedge ​ Interest Expense ​ $ 1,361 ​ $ (120) ​ ​ Income tax benefit ​ (342) ​ 30 ​ ​ Net of tax ​ $ 1,019 ​ $ (90) ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of deferred actuarial loss and prior service cost Operating expenses ​ $ 340 ​ $ 257 ​ Income tax expense ​ (85) ​ (64) ​ Net of tax ​ $ 255 ​ $ 193 ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications ​ $ 1,274 ​ $ 103

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Apr. 04, 2021
Derivative Financial Instruments
Schedule of derivative instruments recorded at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Asset Derivatives ​ ​ ​ ​ April 4, 2021 ​ December 31, 2020 ​ March 31, 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 ​ ​ 403 ​ ​ 877 ​ ​ — Interest rate contracts ​ Other long-term liabilities ​ ​ (157) ​ ​ 585 ​ ​ — Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ 246 ​ $ 1,462 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total asset derivatives ​ ​ ​ $ 246 ​ $ 1,462 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) ​ Liability Derivatives ​ ​ ​ ​ April 4, 2021 ​ December 31, 2020 ​ March 31, 2020 ​ Balance Sheet Classifications Fair Value Fair Value Fair Value Derivatives designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other accrued liabilities ​ ​ (5,139) ​ ​ (5,251) ​ ​ (7,689) Interest rate contracts ​ Other long-term liabilities ​ ​ (6,495) ​ ​ (11,633) ​ ​ (22,795) Total derivatives designated as hedging instruments under ASC 815 ​ ​ ​ $ (11,634) ​ $ (16,884) ​ $ (30,484) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ Other current assets ​ $ 398 ​ $ — ​ $ — Interest rate contracts ​ Other accrued liabilities ​ ​ (4,797) ​ ​ (4,875) ​ ​ — Interest rate contracts ​ Other long-term liabilities ​ ​ (7,353) ​ ​ (9,032) ​ ​ — Total derivatives not designated as hedging instruments under ASC 815 ​ ​ ​ $ (11,752) ​ $ (13,907) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liability derivatives ​ ​ ​ $ (23,386) ​ $ (30,791) ​ $ (30,484)
Schedule of derivative assets at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Assets (Amounts in thousands) April 4, 2021 December 31, 2020 March 31, 2020 Derivatives Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current $ — $ — $ — Interest Rate Swap Agreements — Noncurrent ​ — ​ ​ — ​ ​ — Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current 801 ​ 877 ​ — Interest Rate Swap Agreements — Noncurrent ​ — ​ ​ 585 ​ ​ — ​ $ 801 $ 1,462 $ —
Schedule of derivative liabilities at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Liabilities (Amounts in thousands) ​ April 4, 2021 December 31, 2020 March 31, 2020 Derivatives Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current ​ $ (5,139) $ (5,251) $ (7,689) Interest Rate Swap Agreements — Noncurrent ​ ​ (6,495) ​ ​ (11,633) ​ ​ (22,795) Derivatives Not Designated as Hedging Instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest Rate Swap Agreements — Current ​ (4,797) ​ (4,875) ​ — Interest Rate Swap Agreements — Noncurrent ​ ​ (7,510) ​ ​ (9,032) ​ ​ — ​ ​ $ (23,941) $ (30,791) $ (30,484)
Schedule of gains and losses before taxes on derivatives designated as cash flow hedges	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (Loss) ​ (Loss) Gain Reclassified from ​ ​ Recognized in AOCL ​ AOCL into Operations (Amounts in thousands) 2021 2020 2021 ​ 2020 Interest Rate Swap Agreements ​ $ 3,883 $ (28,794) $ (1,361) $ 120 Total $ 3,883 $ (28,794) $ (1,361) $ 120

Leases (Tables)

Leases (Tables)	3 Months Ended
	Apr. 04, 2021
Operating Leases
Schedule of components of lease cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) ​ April 4, 2021 ​ March 31, 2020 Finance lease expense ​ ​ ​ ​ ​ ​ Amortization of ROU assets ​ $ 157 ​ $ — Interest on lease liabilities ​ ​ 19 ​ ​ — Operating lease cost ​ ​ 6,130 ​ 6,263 Short-term lease cost ​ ​ 1,465 ​ ​ 1,602 Variable lease cost ​ ​ 1,338 ​ ​ 1,466 Total lease cost ​ $ 9,109 ​ $ 9,331
Schedule of other information related to leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) ​ April 4, 2021 ​ March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows for operating leases ​ $ 5,208 ​ ​ $ 1,587 ​ Operating cash flows for finance leases ​ ​ 76 ​ ​ ​ — ​ Financing cash flows for finance leases ​ ​ 19 ​ ​ ​ — ​ Operating Leases ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for lease liabilities ​ ​ 79 ​ ​ 329 ​ Finance Leases ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for lease liabilities ​ ​ 439 ​ ​ ​ — ​ ​ Additional information related to our operating leases for the three months ended April 4, 2021 is as follows: ​ ​ ​ ​ ​ ​ Weighted-average remaining lease term (in years) ​ ​ 18.77 ​ Weighted-average discount rate ​ ​ 6.89 % ​ ​ ​ ​ ​ ​ ​ Weighted-average remaining lease term (in years) ​ ​ 3.43 ​ Weighted-average discount rate ​ ​ 3.83 %
Schedule of supplemental balance sheet information of leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) ​ April 4, 2021 ​ December 31, 2020 ​ March 31, 2020 Operating Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Right of use assets, net ​ $ 194,768 ​ $ 196,711 ​ $ 194,519 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term lease liabilities ​ ​ 10,037 ​ ​ 13,727 ​ ​ 10,490 Long-term lease liabilities ​ ​ 188,573 ​ ​ 185,823 ​ ​ 186,062 Total operating lease obligation ​ $ 198,610 ​ $ 199,550 ​ $ 196,552 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment, at cost ​ $ 2,867 ​ $ 2,428 ​ $ — Accumulated depreciation ​ (405) ​ (248) ​ — Total property and equipment, net ​ 2,462 ​ 2,180 ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term lease liabilities ​ $ 510 ​ $ 327 ​ $ — Long-term lease liabilities ​ ​ 1,789 ​ ​ 1,609 ​ ​ — Total finance lease obligation ​ $ 2,299 ​ $ 1,936 ​ $ —
Schedule of maturities of noncancelable operating lease liabilities	​ ​ ​ ​ ​ ​ ​ ​ (Amounts in thousands) As of April 4, 2021 ​ ​ Finance Leases ​ Operating Leases Remaining in 2021 ​ $ 398 ​ $ 21,685 2022 ​ 767 ​ 22,417 2023 ​ 769 ​ 21,955 2024 ​ 502 ​ 20,206 2025 ​ 24 ​ 18,127 Thereafter ​ — ​ 259,490 Total ​ $ 2,460 ​ $ 363,880 Less: present value discount ​ (161) ​ (165,270) Lease liability ​ $ 2,299 ​ $ 198,610

Business Segments (Tables)

Business Segments (Tables)	3 Months Ended
	Apr. 04, 2021
Business Segments
Schedule of information reflecting long-lived assets, revenues and income before income taxes by domestic and foreign categories	​ The following information reflects our long-lived assets (which consists of property and equipment, right-of-use operating leases and intangible assets) as of April 4, 2021, December 31, 2020 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of (Amounts in thousands) April 4, 2021 December 31, 2020 March 31, 2020 Domestic ​ $ 2,312,048 ​ $ 2,317,009 ​ $ 2,368,183 Foreign ​ ​ 131,207 ​ ​ 134,805 ​ ​ 122,239 Total ​ ​ 2,443,255 ​ ​ 2,451,814 ​ ​ 2,490,422 ​ Revenues and loss before income taxes by domestic and foreign categories as of or for the three months ended April 4, 2021 and March 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic Foreign Total 2021 ​ (Amounts in thousands) Revenues ​ $ 78,673 ​ $ 3,351 ​ $ 82,024 Loss before income taxes ​ (121,192) ​ (6,517) ​ (127,709) 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 89,496 ​ $ 13,007 ​ $ 102,503 Loss before income taxes ​ (102,362) ​ (4,233) ​ (106,595)

Pension Benefits (Tables)

Pension Benefits (Tables)	3 Months Ended
	Apr. 04, 2021
Pension Benefits
Summary of pension costs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended (Amounts in thousands) April 4, 2021 ​ March 31, 2020 Service cost ​ $ 275 ​ $ 325 Interest cost ​ 1,275 ​ 1,623 Expected return on plan assets ​ (3,069) ​ (3,279) Amortization of net actuarial loss ​ 340 ​ 257 Total net periodic benefit ​ $ (1,179) ​ $ (1,074)
Schedule of weighted average assumptions used to determine benefit obligations and net cost	Weighted-Average Assumptions Used To Determine Net Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ April 4, 2021 ​ March 31, 2020 ​ Discount rate ​ 2.20 % 3.00 % Rate of compensation increase N/A N/A Expected return on plan assets ​ 5.75 % 6.50 %

General - Basis of Presentati_4

General - Basis of Presentation (Details) $ in Thousands	3 Months Ended
	Apr. 04, 2021USD ($)itempayment	Dec. 31, 2020USD ($)	Apr. 30, 2020USD ($)	Apr. 22, 2020USD ($)	Mar. 31, 2020USD ($)
Summary of Significant Accounting Policies
Number of parks owned or operated | item	27
Number of reporting units | item	1
Number of upfront payments | payment	1
Initial membership term	12 months
COVID 19 Considerations
Percentage of base salaries reduced for full-time salaried employees					25.00%
Transformation Initiative
Total transformation costs	$ 9,696
Allowance for Doubtful Accounts Receivable	8,500	$ 3,100			$ 7,600
Valuation allowance	129,400	128,200			132,200
Accrued interest and penalties, income taxes	$ 0	$ 0			0
Number of contracts in a typical international agreement | item	1
Number of distinct promises within a typical international agreement | item	3
Other expense. net
Transformation Initiative
Consultant costs	$ 6,787
Technology modernization costs	2,094
Employee termination costs	$ 815
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%
Senior Unsecured 2025 Notes
COVID 19 Considerations
Debt instrument, face amount			$ 725,000
Interest rate, stated percentage			7.00%
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
Mexico
Summary of Significant Accounting Policies
Number of parks owned or operated | item	2
Canada
Summary of Significant Accounting Policies
Number of parks owned or operated | item	1

General - Basis of Presentati_5

General - Basis of Presentation - Earnings Per Common Share (Details) - shares	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
(Loss) Earnings Per Common Share
Antidilutive stock options excluded from computation of diluted shares outstanding (in shares)	6,199,000	5,907,000

General - Basis of Presentati_6

General - Basis of Presentation - Stock Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Stock Benefit Plans
Stock-based compensation	$ 6,637	$ 4,280
Payment of cash dividends	$ 201	21,367
Performance awards
Stock Benefit Plans
Aggregate payout if targets achieved (in shares)	186,000
Unrecognized compensation cost	$ 9,300
Stock-based compensation	0
Dividend Equivalent Rights
Stock Benefit Plans
Payment of cash dividends	200
Long Term Incentive Plan
Stock Benefit Plans
Stock-based compensation	6,562	4,205
Employee Stock Purchase Plan
Stock Benefit Plans
Stock-based compensation	$ 75	$ 75

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) $ in Thousands	Jan. 01, 2020USD ($)	Apr. 04, 2021USD ($)item	Mar. 31, 2020USD ($)	Jan. 01, 2021USD ($)	Jan. 31, 2020USD ($)
Revenue
Revenues		$ 82,024	$ 102,503
Number of distinct obligations within international agreements | item		3
Long-term contracts
Revenue
Revenues		$ 12,170	15,852
Contract with customer, liability				$ 77,600	$ 85,100
Contract with customer, liability, revenue recognized	$ 10,200	8,400
Short-term contracts and other
Revenue
Revenues		69,854	86,651
Park admissions
Revenue
Revenues		44,334	59,806
Park admissions | Long-term contracts
Revenue
Revenues		7,010	5,762
Park admissions | Short-term contracts and other
Revenue
Revenues		37,324	54,044
Park food, merchandise and other
Revenue
Revenues		31,224	29,806
Park food, merchandise and other | Long-term contracts
Revenue
Revenues		997	820
Park food, merchandise and other | Short-term contracts and other
Revenue
Revenues		30,227	28,986
Sponsorship international agreements and accommodations
Revenue
Revenues		6,466	12,891
Sponsorship international agreements and accommodations | Long-term contracts
Revenue
Revenues		4,163	9,270
Sponsorship international agreements and accommodations | Short-term contracts and other
Revenue
Revenues		$ 2,303	$ 3,621

Revenue - Performance Obligatio

Revenue - Performance Obligations (Details) - Long-term contracts - USD ($) $ in Millions	Apr. 04, 2021	Mar. 31, 2020
Revenue
Performance obligation	$ 86.7	$ 70.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-05
Revenue
Performance obligation	$ 100.8
Expected timing of satisfaction, period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-03
Revenue
Performance obligation	$ 18.5
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-02
Revenue
Performance obligation	$ 8.9
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue
Performance obligation	$ 2.3
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	Apr. 22, 2020	Oct. 18, 2019	Oct. 17, 2019	Apr. 13, 2017	Jan. 31, 2017	Jun. 16, 2016	Mar. 31, 2020	Apr. 04, 2021	Mar. 31, 2020	Dec. 31, 2020	Apr. 30, 2020	Apr. 08, 2020	Apr. 07, 2020
Summary of Long-term debt
Loss on debt extinguishment, net									$ 1,019
LIBOR
Summary of Long-term debt
Basis spread on variable rate			2.00%
Amended And Restated Revolving Loan
Summary of Long-term debt
Maximum borrowing capacity								$ 481,000
Long-term line of credit							$ 40,000		40,000
Letters of credit outstanding, amount							21,300	$ 20,200	21,300	$ 21,000
Commitment fee percentage								0.625%
Amended And Restated Term Loan B
Summary of Long-term debt
Maximum borrowing capacity								$ 479,000
Loss on debt extinguishment, net	$ 5,100
Repayment of debt	315,000
Amended And Restated Term Loan B As Amended June 2017
Summary of Long-term debt
Long-term debt							794,000	$ 479,000	794,000	479,000
Amended And Restated Term Loan B As Amended June 2017 | LIBOR
Summary of Long-term debt
Basis spread on variable rate								1.75%
Second Amended and Restated Revolving Loan
Summary of Long-term debt
Maximum borrowing capacity												$ 481,000	$ 350,000
Long-term line of credit							40,000	$ 0	40,000	0
Incremental borrowing capacity								131,000				$ 131,000
Repayment of debt	315,000
Second Amended and Restated Term Loan B
Summary of Long-term debt
Maximum borrowing capacity							350,000		350,000		$ 481,000
Basis spread reduction		0.25%
Incremental borrowing capacity											131,000
Long-term debt							794,000	$ 479,000	794,000	479,000
Interest rate, stated percentage								3.00%
Annual interest cost savings from borrowing rate reduction		$ 300
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
Payments of debt issuance costs						$ 4,700
Loss on debt extinguishment, net							1,000
Long-term debt							949,490	$ 949,490	949,490	949,490
Debt instrument, face amount						$ 300,000
Interest rate, stated percentage						4.875%
Proceeds from issuance of debt utilized for extinguishment of existing debt instruments						$ 150,000
Periodic payment of interest				$ 24,400	$ 9,100		23,100
Pre-payment							50,500
Senior Unsecured 2024 Notes Add-on
Summary of Long-term debt
Payments of debt issuance costs				3,900
Debt instrument, face amount				$ 700,000
Interest rate, stated percentage				4.875%
Senior Unsecured 2025 Notes
Summary of Long-term debt
Long-term debt								725,000		725,000
Debt instrument, face amount											$ 725,000
Interest rate, stated percentage											7.00%
Periodic payment of interest								25,400
Period payment of interest - first payment								35,100
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
Payments of debt issuance costs				$ 2,600
Long-term debt							$ 500,000	$ 500,000	$ 500,000	$ 500,000
Debt instrument, face amount				$ 500,000
Interest rate, stated percentage				5.50%

Long-Term Indebtedness - Schedu

Long-Term Indebtedness - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Summary of Long-term debt
Net discount	$ (4,080)	$ (4,357)	$ (6,002)
Deferred financing costs	(25,049)	(26,492)	(13,694)
Total debt	2,624,361	2,622,641	2,263,794
Less current portion of long-term debt			(8,000)
Less short-term borrowings			(40,000)
Total long-term debt	2,624,361	2,622,641	2,215,794
Second Amended and Restated Term Loan B
Summary of Long-term debt
Long-term debt	479,000	479,000	794,000
Second Amended and Restated Revolving Loan
Summary of Long-term debt
Long-term line of credit	0	0	40,000
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
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	$ 2,700,500	$ 2,693,300	$ 1,952,400

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Accumulated other comprehensive loss, net of tax
Beginning balance	$ (1,158,547)	$ (716,118)
Net current period change	1,274
Amounts reclassified from AOCI	935
Ending balance	(1,236,464)	(852,864)
Cumulative Translation Adjustment
Accumulated other comprehensive loss, net of tax
Beginning balance	(27,412)
Amounts reclassified from AOCI	(2,402)
Ending balance	(29,814)
Cash Flow Hedges
Accumulated other comprehensive loss, net of tax
Beginning balance	(16,819)
Net current period change	1,361
Amounts reclassified from AOCI	3,883
Ending balance	(11,575)
Defined Benefit Plans
Accumulated other comprehensive loss, net of tax
Beginning balance	(57,642)
Net current period change	340
Ending balance	(57,302)
Income Taxes
Accumulated other comprehensive loss, net of tax
Beginning balance	5,369
Net current period change	(427)
Amounts reclassified from AOCI	(546)
Ending balance	4,396
Accumulated other comprehensive loss
Accumulated other comprehensive loss, net of tax
Beginning balance	(96,504)	(74,710)
Ending balance	$ (94,295)	$ (110,423)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Reclassifications out of accumulated other comprehensive income (loss):
Income tax benefit	$ (31,870)	$ (22,049)
Total reclassifications	(935)
Reclassification out of AOCI
Reclassifications out of accumulated other comprehensive income (loss):
Total reclassifications	1,274	103
Reclassification out of AOCI | Amortization of loss on interest rate hedge
Reclassifications out of accumulated other comprehensive income (loss):
Operating expenses	1,361	(120)
Income tax benefit	(342)	30
Total reclassifications	1,019	(90)
Reclassification out of AOCI | Amortization of deferred actuarial loss and prior service cost
Reclassifications out of accumulated other comprehensive income (loss):
Operating expenses	340	257
Income tax benefit	(85)	(64)
Total reclassifications	$ 255	$ 193

Derivative Financial Instrume_3

Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Apr. 22, 2020	Apr. 04, 2021	Mar. 31, 2020	Apr. 30, 2020	Aug. 31, 2019	Jun. 30, 2019
Derivative Financial Instruments
Repayment of borrowings		$ 2,000	$ 117,510
Interest expense		$ 38,460	27,486
Reclassification out of AOCI
Derivative Financial Instruments
Interest expense	$ 14,900
Second Amended and Restated Term Loan B
Derivative Financial Instruments
Repayment of borrowings	$ 315,000
June 2019 Swap Agreements
Derivative Financial Instruments
Notional amount						$ 300,000
August 2019 Swap Agreements
Derivative Financial Instruments
Notional amount					$ 400,000
Modified June 2019 Swap Agreement
Derivative Financial Instruments
Notional amount			100,000
Unmodified June 2019 Swap Agreements
Derivative Financial Instruments
Notional amount			$ 200,000
April 2020 Counter-agreements
Derivative Financial Instruments
Notional amount				$ 300,000

Derivative Financial Instrume_4

Derivative Financial Instruments - Fair Value of Derivative Financial Instruments In Asset Position (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Derivative Financial Instruments
Assets derivatives	$ 246	$ 1,462
Liability derivatives	(23,386)	(30,791)	$ (30,484)
Derivatives Designated as Cash Flow Hedges
Derivative Financial Instruments
Liability derivatives	(11,634)	(16,884)	(30,484)
Derivatives Designated as Cash Flow Hedges | Interest rate Contracts | Other accrued liabilities
Derivative Financial Instruments
Liability derivatives	(5,139)	(5,251)	(7,689)
Derivatives Designated as Cash Flow Hedges | Interest rate Contracts | Other long-term liabilities
Derivative Financial Instruments
Liability derivatives	(6,495)	(11,633)	$ (22,795)
Derivatives Not Designated as Hedging Instruments
Derivative Financial Instruments
Assets derivatives	246	1,462
Liability derivatives	(11,752)	(13,907)
Derivatives Not Designated as Hedging Instruments | Interest rate Contracts | Other current assets
Derivative Financial Instruments
Assets derivatives	403	877
Liability derivatives	398
Derivatives Not Designated as Hedging Instruments | Interest rate Contracts | Other accrued liabilities
Derivative Financial Instruments
Liability derivatives	(4,797)	(4,875)
Derivatives Not Designated as Hedging Instruments | Interest rate Contracts | Other long-term liabilities
Derivative Financial Instruments
Assets derivatives	(157)	585
Liability derivatives	$ (7,353)	$ (9,032)

Derivative Financial Instrume_5

Derivative Financial Instruments - Derivative Instruments Recorded at Fair Value (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Derivative Financial Instruments
Derivative Assets	$ 246	$ 1,462
Derivative Liabilities	(23,386)	(30,791)	$ (30,484)
Interest Rate Swap
Derivative Financial Instruments
Derivative Assets	801	1,462
Derivative Liabilities	(23,941)	(30,791)	(30,484)
Derivatives Designated as Cash Flow Hedges
Derivative Financial Instruments
Derivative Liabilities	(11,634)	(16,884)	(30,484)
Derivatives Designated as Cash Flow Hedges | Interest Rate Swap
Derivative Financial Instruments
Derivative Liabilities - Current	(5,139)	(5,251)	(7,689)
Derivative Liabilities - Noncurrent	(6,495)	(11,633)	$ (22,795)
Derivatives Not Designated as Hedging Instruments
Derivative Financial Instruments
Derivative Assets	246	1,462
Derivative Liabilities	(11,752)	(13,907)
Derivatives Not Designated as Hedging Instruments | Interest Rate Swap
Derivative Financial Instruments
Derivative Assets - Current	801	877
Derivative Assets - Noncurrent		585
Derivative Liabilities - Current	(4,797)	(4,875)
Derivative Liabilities - Noncurrent	$ (7,510)	$ (9,032)

Derivative Financial Instrume_6

Derivative Financial Instruments - Gains and Losses before Taxes on Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Derivative Financial Instruments
Gain (Loss) recognized in AOCL	$ 3,883	$ (28,794)
(Loss) Gain Reclassified from AOCL into Operations (Effective Portion)	(1,361)	120
Loss to be reclassified from AOCI to operations during the next twelve months	5,100
Interest Rate Swap
Derivative Financial Instruments
Gain (Loss) recognized in AOCL	3,883	(28,794)
(Loss) Gain Reclassified from AOCL into Operations (Effective Portion)	(1,361)	$ 120
Derivatives Not Designated as Hedging Instruments
Derivative Financial Instruments
Loss recognized in Interest Expense	$ 100

Commitments and Contingencies (

Commitments and Contingencies (Details)

Dec. 03, 2020lawsuit

Apr. 21, 2020claim

Apr. 08, 2020claim

Jan. 07, 2016USD ($)

Apr. 01, 1998USD ($)

May 30, 2021USD ($)

Apr. 30, 2020lawsuit

Feb. 29, 2020claim

Apr. 04, 2021USD ($)multiple

Mar. 31, 2020USD ($)

Jan. 02, 2022USD ($)

Dec. 31, 2020USD ($)

Dec. 31, 2017USD ($)lawsuit

Apr. 07, 2017item

Details of commitments and contingencies

Acquisition of capital stock of the former Six Flags Entertainment Corporation, paid in cash

$ 976,000,000

Redemption value of noncontrolling interests

$ 523,400,000

Additions to property and equipment

23,133,000

$ 53,458,000

Privacy Class Action Lawsuits | Pending Litigation

Details of commitments and contingencies

Number of claims filed | lawsuit

4

Number of lawsuits stayed pending final approval of settlement | lawsuit

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

Multi-layered general liability policies

Details of commitments and contingencies

Excess liability coverage per occurrence

100,000,000

Self-insured retention per occurrence

2,000,000

Deductible per occurrence applicable to all claims in the policy year

500,000

Workers' compensation claims

Details of commitments and contingencies

Deductible per occurrence applicable to all claims in the policy year

750,000

Workers' compensation claims | November 16, 2001 - November 15, 2003

Details of commitments and contingencies

Deductible per occurrence applicable to all claims in the policy year

500,000

Information security and privacy liability insurance policy

Details of commitments and contingencies

Self-insured retention per occurrence

250,000

Insurance value maintained

10,000,000

Partnerships That Own Partnership Parks

Details of commitments and contingencies

Total loans receivable

288,300,000

$ 239,300,000

$ 288,300,000

Amended And Restated Term Loan B As Amended June 2017

Details of commitments and contingencies

Additional contingent borrowing capacity

$ 350,000,000

Six Flags over Georgia

Details of commitments and contingencies

Limited partner interests owned (as a percent)

31.40%

Remaining redeemable units (as a percent)

68.60%

Six Flags over Texas

Details of commitments and contingencies

Limited partner interests owned (as a percent)

53.90%

Remaining redeemable units (as a percent)

46.10%

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

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

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 Georgia

Details of commitments and contingencies

Purchase price of partnership units

$ 1,000,000

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

33,300,000

Additions to property and equipment

$ 11,000,000

Forecast | Six Flags over Texas

Details of commitments and contingencies

Purchase price of partnership units

$ 1,200,000

Leases - Additional Information

Leases - Additional Information (Details)	3 Months Ended
	Apr. 04, 2021
Minimum
Leases
Term of contract	1 year
Maximum
Leases
Term of contract	44 years
Renewal term	20 years
Option to terminate, term	1 year

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Operating Leases
Amortization of ROU assets	$ 157
Interest on lease liabilities	19
Operating lease cost	6,130	$ 6,263
Short-term lease cost	1,465	1,602
Variable lease cost	1,338	1,466
Total lease cost	9,109	9,331
Operating cash flows from operating leases	5,208	1,587
Operating cash flows from finance leases	76
Financing cash flows for finance leases	19
ROU assets obtained in exchange for operating lease liabilities	79	$ 329
ROU assets obtained in exchange for finance lease liabilities	$ 439
Weighted-average remaining lease term (in years)	18 years 9 months 7 days
Weighted-average discount rate	6.89%
Weighted-average remaining finance lease term (in years)	3 years 5 months 4 days
Weighted-average discount rate	3.83%

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Leases
Right of Use Assets, net	$ 194,768	$ 196,711	$ 194,519
Short-term lease liabilities	10,037	13,727	10,490
Long-term lease liabilities	188,573	185,823	186,062
Operating Lease, Liability, Total	$ 198,610	199,550	196,552
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseLiabilityCurrent us-gaap:OperatingLeaseLiabilityNoncurrent
Property and equipment, at cost	$ 2,427,318	2,408,690	2,364,872
Accumulated depreciation	(1,182,641)	(1,157,403)	(1,073,198)
Total property and equipment, net	1,244,677	1,251,287	$ 1,291,674
Total finance lease obligations	2,299
Finance Leases
Leases
Property and equipment, at cost	2,867	2,428
Accumulated depreciation	(405)	(248)
Total property and equipment, net	2,462	2,180
Short-term lease liabilities	510	327
Long-term lease liabilities	1,789	1,609
Total finance lease obligations	$ 2,299	$ 1,936

Leases - Future Minimum Lease O

Leases - Future Minimum Lease Obligations (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Operating Leases
Remaining in 2021	$ 21,685
2022	22,417
2023	21,955
2024	20,206
2025	18,127
Thereafter	259,490
Total	363,880
Less: present value discount	(165,270)
Lease liability	198,610	$ 199,550	$ 196,552
Finance Leases
Remaining in 2021	398
2022	767
2023	769
2024	502
2025	24
Total	2,460
Less : present value discount	(161)
Lease Liability	$ 2,299

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Dec. 31, 2020	Mar. 31, 2020
Changes in redeemable noncontrolling interests
Redeemable noncontrolling interests	$ 523,376	$ 523,376	$ 529,276
Six Flags over Texas
Changes in redeemable noncontrolling interests
Redeemable noncontrolling interests	242,600
Six Flags over Georgia
Changes in redeemable noncontrolling interests
Redeemable noncontrolling interests	$ 280,800

Business Segments - Information

Business Segments - Information by Geographic Region (Details) $ in Thousands	3 Months Ended
	Apr. 04, 2021USD ($)item	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Business segment information by geographical areas
Number of parks owned or operated | item	27
Long-lived assets	$ 2,443,255	$ 2,490,422	$ 2,451,814
Revenues	82,024	102,503
Income (loss) before income taxes	$ (127,709)	(106,595)
Mexico
Business segment information by geographical areas
Number of parks owned or operated | item	2
Canada
Business segment information by geographical areas
Number of parks owned or operated | item	1
Domestic
Business segment information by geographical areas
Long-lived assets	$ 2,312,048	2,368,183	2,317,009
Revenues	78,673	89,496
Income (loss) before income taxes	(121,192)	(102,362)
Foreign
Business segment information by geographical areas
Long-lived assets	131,207	122,239	$ 134,805
Revenues	3,351	13,007
Income (loss) before income taxes	$ (6,517)	$ (4,233)

Pension Benefits (Details)

Pension Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 31, 2020
Net periodic benefit cost:
Service cost	$ 275	$ 325
Interest cost	1,275	1,623
Expected return on plan assets	(3,069)	(3,279)
Amortization of net actuarial loss	340	257
Total net periodic benefit	$ (1,179)	$ (1,074)
Weighted average assumptions used to determine net cost
Discount rate	2.20%	3.00%
Expected return on plan assets	5.75%	6.50%
Employer contributions		$ 1,500

Stock Repurchase Plans and Sh_2

Stock Repurchase Plans and Shareholder Rights Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	49 Months Ended
	Mar. 31, 2020	Apr. 23, 2021	Mar. 31, 2021	Aug. 31, 2020	Mar. 30, 2017
Stock Repurchase Plans and Shareholder Rights Plan
Value of shares repurchased	$ 6
Amount of reduction in incremental revolving credit commitments required to allow repurchase of common stock				$ 131,000
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					$ 500,000
Total number of shares purchased (in shares)		4,607,000
Value of shares repurchased		$ 268,300
Shares acquired, average cost (in dollars per share)		$ 58.25
Permitted dollar value of repurchases remaining		$ 231,700

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	1 Months Ended
	Apr. 27, 2021USD ($)
Subsequent Event
Subsequent Events
Payment received under an international agreement	$ 11.3