Allegiant Travel (ALGT) 10-Q 31 Oct 19 2019 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 28, 2019
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-33166
Entity Registrant Name	Allegiant Travel Co
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	20-4745737
Entity Address, Address Line One	1201 North Town Center Drive
Entity Address, City or Town	Las Vegas,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89144
City Area Code	702
Local Phone Number	851-7300
Title of 12(b) Security	Common stock, par value $.001
Trading Symbol	ALGT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	true
Entity Common Stock, Shares Outstanding		16,288,448
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001362468
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3

Consolidated Balance Sheets (Cu

Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
CURRENT ASSETS
Cash and cash equivalents	$ 88,114	$ 81,520
Restricted cash	20,475	14,391
Short-term investments	314,822	314,464
Accounts receivable	31,450	36,014
Expendable parts, supplies and fuel, net	27,210	19,516
Prepaid expenses and other current assets	43,356	29,343
TOTAL CURRENT ASSETS	525,427	495,248
Property and equipment, net	2,102,815	1,847,268
Long-term investments	39,057	51,526
Deferred major maintenance, net	99,564	67,873
Operating lease right-of-use assets, net	22,433	0
Deposits and other assets	45,184	36,753
TOTAL ASSETS:	2,834,480	2,498,668
CURRENT LIABILITIES
Accounts payable	21,493	27,452
Accrued liabilities	121,399	122,027
Air traffic liability	267,676	212,230
Current maturities of long-term debt and finance lease obligations, net of related costs	138,685	152,287
TOTAL CURRENT LIABILITIES	549,253	513,996
Long-term debt and finance lease obligations, net of current maturities and related costs	1,213,299	1,119,446
Deferred income taxes	211,801	164,027
Other noncurrent liabilities	33,519	10,878
TOTAL LIABILITIES:	2,007,872	1,808,347
SHAREHOLDERS' EQUITY
Common stock, par value $.001	23	23
Treasury shares	(620,655)	(605,037)
Additional paid in capital	285,318	270,935
Accumulated other comprehensive income (loss), net	29	(661)
Retained earnings	1,161,893	1,025,061
TOTAL EQUITY:	826,608	690,321
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY:	$ 2,834,480	$ 2,498,668

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
OPERATING REVENUES:
Passenger	$ 391,222	$ 355,100	$ 1,265,978	$ 1,157,443
Third party products	18,207	15,921	53,557	44,045
Fixed fee contracts	19,797	14,791	42,859	33,000
Other	7,283	7,297	17,498	20,845
Total operating revenues	436,509	393,109	1,379,892	1,255,333
OPERATING EXPENSES:
Salary and benefits	107,586	97,706	340,589	312,314
Aircraft fuel	104,583	113,525	324,253	342,006
Station operations	43,522	43,128	128,357	122,265
Depreciation and amortization	39,436	34,658	114,112	92,641
Maintenance and repairs	24,768	31,983	68,470	75,864
Sales and marketing	17,591	16,798	59,057	54,224
Aircraft lease rental	0	671	0	767
Other	26,907	28,459	73,756	74,881
Total operating expenses	364,393	366,928	1,108,594	1,074,962
OPERATING INCOME	72,116	26,181	271,298	180,371
OTHER (INCOME) EXPENSES:
Interest expense	19,506	14,309	58,531	40,467
Capitalized interest	(903)	0	(3,444)	(279)
Interest income	(3,335)	(2,425)	(10,038)	(6,259)
Loss on debt extinguishment	0	0	3,677	0
Other, net	(57)	(118)	(41)	(408)
Total other expenses	15,211	11,766	48,685	33,521
INCOME BEFORE INCOME TAXES	56,905	14,415	222,613	146,850
PROVISION FOR INCOME TAXES	12,976	(732)	51,017	26,494
NET INCOME	$ 43,929	$ 15,147	$ 171,596	$ 120,356
Earnings per share to common shareholders:
Basic	$ 2.70	$ 0.94	$ 10.55	$ 7.46
Earnings Per Share, Diluted	$ 2.70	$ 0.94	$ 10.54	$ 7.45
Shares used for computation:
Basic	16,037,000	15,957,000	16,037,000	15,929,000
Diluted	16,039,000	15,962,000	16,045,000	15,938,000
Cash dividends declared per share:	$ 0.70	$ 0.70	$ 2.10	$ 2.10

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 43,929	$ 15,147	$ 171,596	$ 120,356
Other comprehensive income:
Change in available for sale securities, net of tax	16	(83)	669	(926)
Foreign currency translation adjustments	17	4	21	218
Change in derivatives, net of tax	0	1,325	0	2,321
Total other comprehensive income	33	1,246	690	1,613
TOTAL COMPREHENSIVE INCOME	$ 43,962	$ 16,393	$ 172,286	$ 121,969

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Statement of Cash Flows [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activities	$ 53,089	$ 43,751
Adjustments to reconcile net income to net cash provided by operating activities:
NET INCOME	171,596	120,356
Depreciation and amortization	114,112	92,641
(Gain)/loss on aircraft and other equipment disposals	(8,553)	2,274
Share-based compensation expense	13,563	11,043
Deferred income taxes	47,795	21,760
Other adjustments	7,330	1,833
Changes in certain assets and liabilities:
Accounts receivable	4,564	38,005
Prepaid expenses	(13,493)	(6,709)
Accounts payable	(3,655)	(2,437)
Accrued liabilities	(8,158)	5,960
Air traffic liability	55,446	27,432
Deferred major maintenance	(48,081)	(21,699)
Other assets/liabilities	(11,039)	(336)
Net cash provided by operating activities	321,427	290,123
INVESTING ACTIVITIES:
Purchase of investment securities	(397,504)	(263,057)
Proceeds from maturities of investment securities	413,038	355,325
Purchase of property and equipment, including capitalized interest	(350,187)	(273,999)
Other investing activities	10,647	(5,399)
Net cash used in investing activities	(324,006)	(187,130)
Payments of Dividends	(34,214)	(33,919)
FINANCING ACTIVITIES:
Proceeds from the issuance of debt	770,435	191,724
Repurchase of common stock	(18,549)	(3,617)
Principal payments on debt and finance lease obligations	(670,148)	(171,438)
Debt issuance costs	(32,592)	(1,147)
Other financing activities	325	5,834
Net cash provided by (used in) financing activities	15,257	(12,563)
Net change in cash, cash equivalents, and restricted cash	12,678	90,430
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	95,911	70,639
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD	108,589	161,069
CASH PAYMENTS (RECEIPTS) FOR:
Income tax refunds	(2,227)	(41,145)
Property capitalized under operating leases	25,533	0
Flight equipment acquired under finance leases	$ 0	$ 127,625

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Parent [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Common Stock, Shares, Outstanding		16,066,000
Common Stock, Value, Issued		$ 23
Additional paid in capital			$ 253,840
Accumulated other comprehensive income (loss), net							$ (2,840)
Retained Earnings (Accumulated Deficit)						$ 907,943
Treasury Stock, Value					$ (605,655)
Stockholders' Equity Attributable to Parent				$ 553,311
Stock issued under employee stock purchase plan		10,000
StockIssuedDuringPeriodSharesStockOptionsSARsExercised		98,000
Stock Issued During Period, Shares, New Issues	0	8,000	0	0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition			$ 13,067	$ 13,067
Treasury Stock, Value, Acquired, Cost Method				(3,617)	(3,617)
Stock Issued During Period, Value, Employee Stock Purchase Plan				1,623	1,623
Dividends, Cash				33,919		33,919
Payments of Dividends	$ 33,919
Treasury Stock, Shares, Acquired		(23,000)
Other Comprehensive Income (Loss), Net of Tax	1,613			2,175		562	1,613
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 120,356			120,356		120,356
Common Stock, Shares, Outstanding		16,161,000
Common Stock, Value, Issued		$ 23
Additional paid in capital			$ 263,034
Accumulated other comprehensive income (loss), net							(2,473)
Retained Earnings (Accumulated Deficit)						991,109
Treasury Stock, Value					(607,025)
Stockholders' Equity Attributable to Parent				$ 644,668
StockIssuedDuringPeriodSharesStockOptionsSARsExercised		0
Stock Issued During Period, Shares, New Issues	0	3,000	0	0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition			$ 3,873	$ 3,873
Treasury Stock, Value, Acquired, Cost Method				(624)	(624)
Payments of Dividends				11,314		11,314
Treasury Stock, Shares, Acquired		(5,000)
Other Comprehensive Income (Loss), Net of Tax	$ 1,246			1,246			1,246
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	15,147			15,147		15,147
Common Stock, Shares, Outstanding		16,159,000
Common Stock, Value, Issued		$ 23
Additional paid in capital			266,907
Accumulated other comprehensive income (loss), net							(1,227)
Retained Earnings (Accumulated Deficit)						994,942
Treasury Stock, Value					(607,649)
Stockholders' Equity Attributable to Parent				652,996
Common Stock, Shares, Outstanding		16,183,000
Common Stock, Value, Issued	23	$ 23
Additional paid in capital	270,935		270,935
Accumulated other comprehensive income (loss), net	(661)						(661)
Retained Earnings (Accumulated Deficit)	1,025,061					1,025,061
Treasury Stock, Value	605,037				(605,037)
Stockholders' Equity Attributable to Parent	690,321			690,321
Stock issued under employee stock purchase plan		20,000
StockIssuedDuringPeriodSharesStockOptionsSARsExercised		124,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition			14,383	14,383
Treasury Stock, Value, Acquired, Cost Method				(18,549)	(18,549)
Stock Issued During Period, Value, Employee Stock Purchase Plan				2,931	2,931
Payments of Dividends	34,214			34,214		34,214
Treasury Stock, Shares, Acquired		(132,000)
Other Comprehensive Income (Loss), Net of Tax	690			690		0	690
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	171,596			171,596
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income				(550)		(550)
Common Stock, Shares, Outstanding		16,305,000
Common Stock, Value, Issued		$ 23
Additional paid in capital			280,783
Accumulated other comprehensive income (loss), net							(4)
Retained Earnings (Accumulated Deficit)						1,128,822
Treasury Stock, Value					(605,115)
Stockholders' Equity Attributable to Parent				804,509
StockIssuedDuringPeriodSharesStockOptionsSARsExercised		0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition			4,535	4,535
Treasury Stock, Value, Acquired, Cost Method				(15,540)	(15,540)
Payments of Dividends				11,409		11,409
Treasury Stock, Shares, Acquired		(110,000)
Other Comprehensive Income (Loss), Net of Tax	33			584		551	33
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	43,929			43,929		43,929
Common Stock, Shares, Outstanding		16,195,000
Common Stock, Value, Issued	23	$ 23
Additional paid in capital	285,318		$ 285,318
Accumulated other comprehensive income (loss), net	29						$ 29
Retained Earnings (Accumulated Deficit)	1,161,893					$ 1,161,893
Treasury Stock, Value	620,655				$ (620,655)
Stockholders' Equity Attributable to Parent	$ 826,608			$ 826,608

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity Parentheticals - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0.70	$ 0.70	$ 2.10	$ 2.10

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited consolidated financial statements include the accounts of Allegiant Travel Company (the “Company”) and its majority-owned operating subsidiaries. The Company's investments in unconsolidated affiliates, which are 50 percent or less owned, are accounted for under the equity or cost method, and are insignificant to the consolidated financial statements. All intercompany balances and transactions have been eliminated. These unaudited consolidated financial statements reflect all normal recurring adjustments which management believes are necessary to present fairly the financial position, results of operations, and cash flows of the Company for the respective periods presented. Certain reclassifications have been made to prior year financial statements to conform to classifications used in the current year. Certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") have been omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company and notes thereto included in the annual report of the Company on Form 10-K for the year ended December 31, 2018 and filed with the Securities and Exchange Commission. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from these estimates. Recent Accounting Pronouncements Recently Adopted Standards In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, Leases (Topic 842), (the "New Lease Standard"). This standard requires leases, other than short-term, to be recognized on the balance sheet as a lease liability and a corresponding right-of-use asset. Lease payments include fixed payments, variable payments based on an index or rate, reasonably certain purchase options, termination penalties, and other payments as required by the standard. Lease payments do not include variable lease payments other than those that depend on an index or rate, any guarantee by the lessee of the lessor’s debt, or any amount allocated to non-lease components. This standard is effective for interim and annual reporting periods beginning after December 15, 2018 and the Company adopted the New Lease Standard as of January 1, 2019. The Company also elected the package of practical expedients, which among other things, does not require reassessment of lease classification. The Company adopted the New Lease Standard using the modified retrospective transition approach as of the effective date as permitted by the amendments in ASU 2018-11, "Targeted Improvements - Leases (Topic 842)." Under this method, the cumulative effect adjustment to the opening balance of retained earnings is recognized at the adoption date. As a result, the Company was not required to adjust its comparative period financial information for effects of the standard or make the new required lease disclosures for periods before the date of adoption on January 1, 2019. The Company's consolidated balance sheet was affected by this standard, but the consolidated statements of income and the Company's liquidity were not significantly impacted. The most significant change to the consolidated balance sheet upon adoption on January 1, 2019 relates to the recognition of new right-of-use (ROU) assets of $18.0 million and operating liabilities of $19.1 million . The Company's accounting for finance leases remains substantially unchanged. See Note 5, "Leases," for more information.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2019
Revenue Recognition [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue Recognition Passenger Revenue Passenger revenue is the most significant category in our reported operating revenues. Passenger revenue is primarily composed of scheduled service revenue (including passenger ticket sales and credit voucher breakage), revenue from ancillary air-related charges (including seat fees, baggage fees, and other travel-related services performed in conjunction with a passenger’s flight), as well as co-brand credit card point redemptions, as outlined below: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Scheduled service $ 200,233 $ 202,796 $ 672,690 $ 677,061 Ancillary air-related charges 187,776 150,095 583,003 472,443 Co-brand redemptions 3,213 2,209 10,285 7,939 Total passenger revenue $ 391,222 $ 355,100 $ 1,265,978 $ 1,157,443 Sales of passenger tickets not yet flown are recorded in air traffic liability. Passenger revenue is recognized when transportation is provided or when ticket voucher breakage occurs, to the extent different from estimated breakage. The contract term of passenger tickets is twelve months and revenue associated with future travel will principally be recognized within this time frame. During the nine months ended September 30, 2019 , $210.1 million was recognized into passenger revenue that was recorded in the air traffic liability balance of $212.2 million at December 31, 2018 . Co-brand redemptions In relation to the travel component of the co-branded credit card contract with Bank of America, the Company has a performance obligation to provide cardholders with points to be used for future travel award redemptions. Therefore, consideration received from Bank of America related to the travel component is deferred based on its relative selling price and is recognized into passenger revenue when the points are redeemed and the transportation is provided. The following table presents the activity of the co-brand point liability as of the dates indicated: Nine Months Ended September 30, (in thousands) 2019 2018 Balance at January 1 $ 10,708 $ 8,903 Points awarded (deferral of revenue) 14,308 10,872 Points redeemed (recognition of revenue) (10,285 ) (7,939 ) Balance at September 30 $ 14,731 $ 11,836 As of September 30, 2019 and 2018 , $10.6 million and $8.1 million , respectively, of the current points liability is reflected in Accrued liabilities and represents our current estimate of revenue to be recognized in the next twelve

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property and Equipment Property and equipment: (in thousands) As of September 30, 2019 As of December 31, 2018 Flight equipment, including pre-delivery deposits $ 2,168,557 $ 1,905,157 Computer hardware and software 158,720 140,385 Land and buildings/leasehold improvements 86,163 85,925 Other property and equipment 142,198 89,778 Total property and equipment 2,555,638 2,221,245 Less accumulated depreciation and amortization (452,823 ) (373,977 ) Property and equipment, net $ 2,102,815 $ 1,847,268 Accrued capital expenditures as of September 30, 2019 and September 30, 2018 were $6.1 million and $3.8 million

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt and finance lease obligations: (in thousands) As of September 30, 2019 As of December 31, 2018 Fixed-rate debt and finance lease obligations due through 2029 (1) $ 215,839 $ 640,806 Variable-rate debt due through 2029 1,136,145 630,927 Total long-term debt and finance lease obligations, net of related costs 1,351,984 1,271,733 Less current maturities, net of related costs (1) 138,685 152,287 Long-term debt and finance lease obligations, net of current maturities and related costs $ 1,213,299 $ 1,119,446 Weighted average fixed-interest rate on debt 3.9 % 5.3 % Weighted average variable-interest rate on debt 4.8 % 4.2 % (1) As of December 31, 2018, $428.0 million of the Company's Unsecured Senior Notes were classified as long-term as management refinanced the borrowings on a long-term basis in February 2019, as discussed below. Maturities of long-term debt and finance lease obligations for the remainder of 2019 and for the next four years and thereafter, in the aggregate, are: remaining in 2019 - $33.0 million ; 2020 - $138.9 million ; 2021 - $133.4 million ; 2022 - $113.8 million ; 2023 - $100.9 million ; and $832.0 million thereafter. Consolidated Variable Interest Entity In March 2019, the Company, through a wholly owned subsidiary, entered into agreements with a trust to borrow $44.0 million secured by one aircraft. The trust was funded on inception. These borrowings bear interest at a blended rate of 3.8 percent , payable in quarterly installments through April 2029, at which time the Company will have a purchase option at a fixed amount. As this transaction is a common control transaction, the Company, as the primary beneficiary, has measured and recorded the assets and liabilities at their carrying values, which were $39.1 million and $44.0 million , respectively, at the time of borrowing. Senior Secured Revolving Credit Facility The Company has a senior secured revolving credit facility under which it is able to borrow up to $81.0 million . There was no balance under this facility as of September 30, 2019 . The facility has a term of 24 months and is based on the value of aircraft placed in the collateral pool. Aircraft remain in the collateral pool for up to two years, and, as of September 30, 2019 , there were four aircraft in the collateral pool. Secured Debt In June 2019, the Company entered into an agreement to borrow $213.0 million secured by 23 aircraft. The borrowing bears interest at a floating rate based on LIBOR, and is payable in quarterly installments over five years . A portion of the proceeds was used for the prepayment of the balance under six existing debt agreements and the repayment of the outstanding balance on the senior secured revolving credit facility. During the second quarter 2019, the Company borrowed a total of $63.4 million under loan agreements secured by spare engines. The borrowings bear interest at a floating rate based on LIBOR, and are payable in quarterly installments, with terms ranging from seven to ten years . Term Loan In February 2019, the Company entered into a Credit and Guaranty Agreement (the “Term Loan”) to borrow $450.0 million , guaranteed by all of the Company's subsidiaries, excluding Sunseeker Resorts Inc. and its subsidiaries, and other insignificant subsidiaries (the "Term Loan Guarantors"). The Term Loan is secured by substantially all property and assets of the Company and the Term Loan Guarantors, excluding aircraft and aircraft engines, and excluding certain other assets. The Term Loan has a five-year term, bears interest based on LIBOR and provides for quarterly interest payments along with quarterly principal payments of $1.1 million through February 2024, at which time the Term Loan is due. The Term Loan may be prepaid at any time without penalty. In connection with the Term Loan, the Company conducted a tender offer for its 5.5 percent senior unsecured obligation, as outlined below. General Unsecured Senior Notes Until February 2019, the Company had outstanding $450.0 million aggregate principal amount of senior unsecured obligations (the "Notes") which bore interest at 5.5 percent per year and matured in July 2019. In connection with the Term Loan discussed above, the Company completed a tender offer in February 2019, whereby it purchased $347.9 million of the Notes, and incurred related debt extinguishment costs of $3.7 million . The remaining $102.1 million of the Notes were paid at their maturity in July 2019. Construction Loan Agreement In March 2019, Sunseeker Florida, Inc. (“SFI”), a wholly-owned subsidiary of the Company, entered into a Construction Loan Agreement with certain lenders affiliated with TPG Sixth Street Partners, LLC (the “Lender”). Under the Construction Loan Agreement, SFI may borrow up to $175.0 million (the “Loan”) to fund the construction of Phase 1 of Sunseeker Resort -Charlotte Harbor (the “Project”). No amount has been drawn under this agreement as of September 30, 2019 . Under the Construction Loan Agreement, the Lender is to provide the final $175.0 million

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value, Measurement Inputs, Disclosure	Fair Value Measurements The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received by selling an asset or paid to transfer a liability in an orderly transaction between market participants. Accounting standards pertaining to fair value measurements establish a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 inputs that are either directly or indirectly observable; and Level 3, defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The Company uses the market approach valuation technique to determine fair value for investment securities. The assets classified as Level 1 consist of money market funds for which original cost approximates fair value. The assets classified as Level 2 consist of commercial paper, municipal debt securities, federal agency debt securities, US Treasury Bonds, and corporate debt securities, which are valued using quoted market prices or alternative pricing sources including transactions involving identical or comparable assets and models utilizing market observable inputs. The Company has no investment securities classified as Level 3. For those assets classified as Level 2 that are not in active markets, the Company obtains fair value from pricing sources using quoted market prices for identical or comparable instruments, and uses pricing models which include all significant observable inputs: maturity dates, issue dates, settlement dates, benchmark yields, reported trades, broker-dealer quotes, issue spreads, benchmark securities, bids, offers and other market related data. These inputs are observable or can be derived from, or corroborated by, observable market data for substantially the full term of the asset. Financial instruments measured at fair value on a recurring basis: As of September 30, 2019 As of December 31, 2018 (in thousands) Total Level 1 Level 2 Total Level 1 Level 2 Cash equivalents Money market funds $ 65,014 $ 65,014 $ — $ 43,281 $ 43,281 $ — Commercial paper 5,731 — 5,731 29,138 — 29,138 Municipal debt securities 4,087 — 4,087 — — — Federal agency debt securities 124 — 124 — — — US Treasury bonds — — — 1,415 — 1,415 Total cash equivalents 74,956 65,014 9,942 73,834 43,281 30,553 Short-term Corporate debt securities 149,854 — 149,854 101,489 — 101,489 Commercial paper 142,656 — 142,656 180,846 — 180,846 Federal agency debt securities 11,510 — 11,510 11,887 — 11,887 Municipal debt securities 7,785 — 7,785 14,252 — 14,252 US Treasury bonds 3,017 — 3,017 5,990 — 5,990 Total short-term 314,822 — 314,822 314,464 — 314,464 Long-term Corporate debt securities 35,996 — 35,996 37,334 — 37,334 US Treasury bonds 3,061 — 3,061 2,901 — 2,901 Federal agency debt securities — — — 11,291 — 11,291 Total long-term 39,057 — 39,057 51,526 — 51,526 Total financial instruments $ 428,835 $ 65,014 $ 363,821 $ 439,824 $ 43,281 $ 396,543 The fair value of the Company’s publicly held long-term debt was determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets; therefore, the Company categorized its publicly held debt as Level 2. The Company's remaining debt is not publicly held, and the Company has determined the estimated fair value of these notes to be Level 3, as certain inputs used to determine the fair value are unobservable and, therefore, could be sensitive to changes in inputs. The Company utilizes the discounted cash flow method to estimate the fair value of Level 3 debt. Carrying value and estimated fair value of long-term debt, including current maturities and without reduction for related costs are as follows: As of September 30, 2019 As of December 31, 2018 (in thousands) Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Hierarchy Level Non-publicly held debt $ 1,259,130 $ 1,053,911 $ 703,372 $ 619,379 3 Publicly held debt — — 450,463 451,026 2 Total long-term debt $ 1,259,130 $ 1,053,911 $ 1,153,835 $ 1,070,405 Due to the short-term nature, carrying amounts of cash, cash equivalents, restricted cash, accounts receivable and accounts payable approximate fair value.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share Basic and diluted earnings per share are computed pursuant to the two-class method. Under this method, the Company attributes net income to two classes: common stock and unvested restricted stock. Unvested restricted stock awards granted to employees under the Company’s Long-Term Incentive Plan are considered participating securities as they receive non-forfeitable rights to cash dividends at the same rate as common stock. Diluted net income per share is calculated using the more dilutive of the two methods. Under both methods, the exercise of employee stock options is assumed using the treasury stock method. The assumption of vesting of restricted stock, however, differs: 1. Assume vesting of restricted stock using the treasury stock method. 2. Assume unvested restricted stock awards are not vested, and allocate earnings to common shares and unvested restricted stock awards using the two-class method. For the three and nine months ended September 30, 2019 and 2018 , respectively, the second method, which assumes unvested awards are not vested, was used in the computation because it was more dilutive than the first method. The following table sets forth the computation of net income per share, on a basic and diluted basis, for the periods indicated (share count and dollar amounts other than per-share amounts in table are in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Basic: Net income $ 43,929 $ 15,147 $ 171,596 $ 120,356 Less net income allocated to participating securities (578 ) (194 ) (2,441 ) (1,602 ) Net income attributable to common stock $ 43,351 $ 14,953 $ 169,155 $ 118,754 Earnings per share, basic $ 2.70 $ 0.94 $ 10.55 $ 7.46 Weighted-average shares outstanding 16,037 15,957 16,037 15,929 Diluted: Net income $ 43,929 $ 15,147 $ 171,596 $ 120,356 Less net income allocated to participating securities (578 ) (194 ) (2,440 ) (1,601 ) Net income attributable to common stock $ 43,351 $ 14,953 $ 169,156 $ 118,755 Earnings per share, diluted $ 2.70 $ 0.94 $ 10.54 $ 7.45 Weighted-average shares outstanding 16,037 15,957 16,037 15,929 Dilutive effect of stock options and restricted stock 56 35 45 42 Adjusted weighted-average shares outstanding under treasury stock method 16,093 15,992 16,082 15,971 Participating securities excluded under two-class method (54 ) (30 ) (37 ) (33 ) Adjusted weighted-average shares outstanding under two-class method 16,039 15,962 16,045 15,938

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies As of September 30, 2019 , the Company had firm commitments to purchase fourteen Airbus A320 series aircraft. The Company's contractual purchase commitments consist primarily of aircraft and engine acquisitions. The total future commitments are as follows: (in thousands) As of September 30, 2019 Remaining in 2019 $ 53,400 2020 157,900 2021 37,900 2022 21,000 Total commitments $ 270,200 Contingencies The Company is subject to certain legal and administrative actions it considers routine to its business activities. The Company believes the ultimate outcome of any pending legal or administrative matters will not have a material adverse impact on its financial position, liquidity or results of operations.

Lease (Notes)

Lease (Notes)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Lessee, Leases [Policy Text Block]	Leases The Company determines if an arrangement is a lease at inception and has lease agreements for office facilities, office equipment, certain airport and terminal facilities, and other space and assets. These commitments have remaining non-cancelable lease terms, with lease expirations which range from 2019 to 2036. As a result of the New Lease Standard, certain real estate and property leases, and various other operating leases have been measured on the balance sheet with a lease liability and right-of-use asset ("ROU"). Airport terminal leases mostly include variable lease payments outside of those based on a fixed index, and are therefore excluded from consideration. Accounting for finance leases is substantially unchanged. ROU assets represent the Company's right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make scheduled lease payments. ROU assets and liabilities are recognized on the lease commencement date based on the present value of lease payments over the lease term. The present value of lease payments is calculated using the incremental borrowing rate at lease commencement, which takes into consideration recent debt issuances as well as other applicable market data available. Lease terms include options to extend when it is reasonably certain that the option will be exercised. Leases with a term of twelve months or less are not recorded on the balance sheet. Additionally, lease and non-lease components are accounted for as a single lease component for real estate agreements. In addition to operating leases, the Company had five aircraft under finance leases as of September 30, 2019 , with remaining terms to 2029. Lease Costs The components of lease costs recognized on the statements of income were as follows: Three Months Ended Nine Months Ended (in thousands) Classification on the Statements of Income September 30, 2019 September 30, 2019 Finance lease costs: Amortization of assets Depreciation and amortization $ 1,629 $ 4,888 Interest on lease liabilities Interest expense 1,306 3,978 Operating lease cost Station operations; Maintenance and repairs; Other operating expense 897 2,634 Variable lease cost Station operations; Maintenance and repairs; Other operating expense 663 1,672 Total lease cost $ 4,495 $ 13,172 Lease position as of September 30, 2019 The table below presents the lease-related assets and liabilities recorded on the balance sheet. As of (in thousands) Classification on the Balance Sheet September 30, 2019 Assets Operating lease assets Operating lease right-of-use assets, net $ 22,433 Finance lease assets Property and equipment, net 113,294 Total lease assets $ 135,727 Liabilities Current Operating Accrued liabilities $ 2,388 Finance Current maturities of long-term debt and finance lease obligations 7,582 Noncurrent Operating Other noncurrent liabilities 21,744 Finance Long-term debt and finance lease obligations 109,878 Total lease liabilities $ 141,592 Weighted-average remaining lease term Operating leases 9.4 years Finance leases 10.1 years Weighted-average discount rate Operating leases 4.3 % Finance leases 4.4 % Other Information The table below presents supplemental cash flow information related to leases during the three and nine months ended September 30, 2019 . Three Months Ended Nine Months Ended (in thousands) September 30, 2019 September 30, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 725 $ 2,190 Operating cash flows for finance leases 1,306 3,978 Financing cash flows for finance leases 1,844 5,472 Maturities of Lease Liabilities The table below indicates the future minimum payments of lease liabilities as of September 30, 2019 . (in thousands) Operating Leases Finance Leases Remaining in 2019 $ 726 $ 3,150 2020 3,566 12,600 2021 3,382 12,600 2022 3,361 11,095 2023 3,213 10,500 Thereafter 15,317 103,459 Total lease payments 29,565 153,404 Less imputed interest (5,433 ) (35,944 ) Total lease obligations 24,132 117,460 Less current obligations (2,388 ) (7,582 ) Long-term lease obligations $ 21,744 $ 109,878 The Company adopted the New Lease Standard on January 1, 2019 as noted above, and as required, the following disclosure is provided for periods prior to adoption. Future annual minimum lease payments as of December 31, 2018 were as follows: (in thousands) Operating Leases Finance Leases 2019 $ 8,102 $ 12,600 2020 6,031 12,600 2021 3,643 12,600 2022 1,630 11,095 2023 1,626 10,500 Thereafter 8,297 103,458 Total lease payments $ 29,329 162,853 Less imputed interest (39,922 ) Total lease obligations 122,931 Less current obligations (7,336 ) Long-term lease obligations $ 115,595

Operating Segments (Notes)

Operating Segments (Notes)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	Segments Operating segments are components of a company for which separate financial and operating information is regularly evaluated and reported to the Chief Operating Decision Maker ("CODM"), and is used to allocate resources and analyze performance. The Company's CODM is the executive leadership team, which reviews information about the Company's three operating segments: the Airline, Sunseeker Resort, and other non-airline. Airline Segment The Airline segment operates as a single business unit and includes all scheduled service air transportation, ancillary air-related products and services, third party products and services, fixed fee contract air transportation and other airline-related revenue. The CODM evaluation includes, but is not limited to, route and flight profitability data, ancillary and third party product and service offering statistics, and fixed fee contract information when making resource allocation decisions with the goal of optimizing consolidated financial results. Sunseeker Resort Segment The Sunseeker Resort segment represents activity related to the development and construction of Sunseeker Resort in Southwest Florida, as well as the operation of Kingsway golf course. Plans for the resort include a 500-room hotel and two towers offering an estimated 180 one, two and three bedroom suites, bar and restaurant options, and other amenities. The golf course is a short drive from the resort site and is considered, from a planning and strategic perspective, to be an additional resort amenity. The construction of Sunseeker Resort is an extension of the Company's leisure travel focus and it is expected that many customers flying to Southwest Florida on Allegiant will elect to stay at this resort and enjoy its amenities. Other non-Airline Segment The other non-airline segment includes the Teesnap golf course management solution and Allegiant Nonstop family entertainment centers. Allegiant Nonstop family entertainment centers are comprised of games, attractions, and food facilities. In July 2019, management began evaluating strategic alternatives for Teesnap, and its business-to-business software as a service offering. As the Company's current strategy has a business to customer focus, rather than business to business, management determined that the best course of action for both entities would be to sell Teesnap. Management expects the sale to be finalized before the end of the second quarter 2020. The carrying value of the disposal group expected to be transferred in the sale is approximately $5.5 million as of September 30, 2019. Selected information for the Company's segments and the reconciliation to the consolidated financial statement amounts are as follows: (in thousands) Airline Sunseeker Resort Other non- airline Consolidated Three Months Ended September 30, 2019 Operating revenue: Passenger $ 391,222 $ — $ — $ 391,222 Third party products 18,207 — — 18,207 Fixed fee contract 19,797 — — 19,797 Other 1,648 251 5,384 7,283 Operating income (loss) 77,335 (1,281 ) (3,938 ) 72,116 Interest expense, net 14,761 507 — 15,268 Depreciation and amortization 38,409 329 698 39,436 Capital expenditures 98,308 16,931 479 115,718 Three Months Ended September 30, 2018 Operating revenue: Passenger $ 355,100 $ — $ — $ 355,100 Third party products 15,921 — — 15,921 Fixed fee contract 14,791 — — 14,791 Other 4,611 94 2,592 7,297 Operating income (loss) 29,727 (1,136 ) (2,410 ) 26,181 Interest expense, net 11,884 — — 11,884 Depreciation and amortization 34,138 47 473 34,658 Capital expenditures 74,799 8,197 3,547 86,543 (in thousands) Airline Sunseeker Resort Other non- airline Consolidated Nine Months Ended September 30, 2019 Operating revenue: Passenger $ 1,265,978 $ — $ — $ 1,265,978 Third party products 53,557 — — 53,557 Fixed fee contract 42,859 — — 42,859 Other 3,578 1,526 12,394 17,498 Operating income (loss) 291,371 (4,199 ) (15,874 ) 271,298 Interest expense, net 43,906 1,143 — 45,049 Depreciation and amortization 110,528 811 2,773 114,112 Capital expenditures 305,356 33,502 11,329 350,187 Nine Months Ended September 30, 2018 Operating revenue: Passenger $ 1,157,443 $ — $ — $ 1,157,443 Third party products 44,045 — — 44,045 Fixed fee contract 33,000 — — 33,000 Other 14,808 94 5,943 20,845 Operating income (loss) 187,731 (1,582 ) (5,778 ) 180,371 Interest expense, net 33,929 — — 33,929 Depreciation and amortization 91,309 64 1,268 92,641 Capital expenditures 240,733 25,541 7,725 273,999 Total assets were as follows as of the dates indicated: (in thousands) September 30, 2019 December 31, 2018 Airline $ 2,689,869 $ 2,422,523 Sunseeker Resort 104,283 56,047 Other non-airline 40,328 20,098 Consolidated $ 2,834,480 $ 2,498,668

Summary of Significant Accoun_2

Summary of Significant Accounting Policies - (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements include the accounts of Allegiant Travel Company (the “Company”) and its majority-owned operating subsidiaries. The Company's investments in unconsolidated affiliates, which are 50 percent or less owned, are accounted for under the equity or cost method, and are insignificant to the consolidated financial statements. All intercompany balances and transactions have been eliminated. These unaudited consolidated financial statements reflect all normal recurring adjustments which management believes are necessary to present fairly the financial position, results of operations, and cash flows of the Company for the respective periods presented. Certain reclassifications have been made to prior year financial statements to conform to classifications used in the current year. Certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") have been omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company and notes thereto included in the annual report of the Company on Form 10-K for the year ended December 31, 2018 and filed with the Securities and Exchange Commission. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from these estimates.
New Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Standards In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, Leases (Topic 842), (the "New Lease Standard"). This standard requires leases, other than short-term, to be recognized on the balance sheet as a lease liability and a corresponding right-of-use asset. Lease payments include fixed payments, variable payments based on an index or rate, reasonably certain purchase options, termination penalties, and other payments as required by the standard. Lease payments do not include variable lease payments other than those that depend on an index or rate, any guarantee by the lessee of the lessor’s debt, or any amount allocated to non-lease components. This standard is effective for interim and annual reporting periods beginning after December 15, 2018 and the Company adopted the New Lease Standard as of January 1, 2019. The Company also elected the package of practical expedients, which among other things, does not require reassessment of lease classification. The Company adopted the New Lease Standard using the modified retrospective transition approach as of the effective date as permitted by the amendments in ASU 2018-11, "Targeted Improvements - Leases (Topic 842)." Under this method, the cumulative effect adjustment to the opening balance of retained earnings is recognized at the adoption date. As a result, the Company was not required to adjust its comparative period financial information for effects of the standard or make the new required lease disclosures for periods before the date of adoption on January 1, 2019. The Company's consolidated balance sheet was affected by this standard, but the consolidated statements of income and the Company's liquidity were not significantly impacted. The most significant change to the consolidated balance sheet upon adoption on January 1, 2019 relates to the recognition of new right-of-use (ROU) assets of $18.0 million and operating liabilities of $19.1 million . The Company's accounting for finance leases remains substantially unchanged. See Note 5, "Leases," for more information.

Operating Segments Asset Held f

Operating Segments Asset Held for Sale (Policies)	9 Months Ended
	Sep. 30, 2019
Long Lived Assets Held-for-sale [Line Items]
Disclosure of Long Lived Assets Held-for-sale [Table Text Block]	In July 2019, management began evaluating strategic alternatives for Teesnap, and its business-to-business software as a service offering. As the Company's current strategy has a business to customer focus, rather than business to business, management determined that the best course of action for both entities would be to sell Teesnap. Management expects the sale to be finalized before the end of the second quarter 2020. The carrying value of the disposal group expected to be transferred in the sale is approximately $5.5 million as of September 30, 2019.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue Recognition [Abstract]
Disaggregation of Revenue [Table Text Block]	Passenger revenue is primarily composed of scheduled service revenue (including passenger ticket sales and credit voucher breakage), revenue from ancillary air-related charges (including seat fees, baggage fees, and other travel-related services performed in conjunction with a passenger’s flight), as well as co-brand credit card point redemptions, as outlined below: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Scheduled service $ 200,233 $ 202,796 $ 672,690 $ 677,061 Ancillary air-related charges 187,776 150,095 583,003 472,443 Co-brand redemptions 3,213 2,209 10,285 7,939 Total passenger revenue $ 391,222 $ 355,100 $ 1,265,978 $ 1,157,443
Contract with Customer, Asset and Liability [Table Text Block]	The following table presents the activity of the co-brand point liability as of the dates indicated: Nine Months Ended September 30, (in thousands) 2019 2018 Balance at January 1 $ 10,708 $ 8,903 Points awarded (deferral of revenue) 14,308 10,872 Points redeemed (recognition of revenue) (10,285 ) (7,939 ) Balance at September 30 $ 14,731 $ 11,836

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	Property and equipment: (in thousands) As of September 30, 2019 As of December 31, 2018 Flight equipment, including pre-delivery deposits $ 2,168,557 $ 1,905,157 Computer hardware and software 158,720 140,385 Land and buildings/leasehold improvements 86,163 85,925 Other property and equipment 142,198 89,778 Total property and equipment 2,555,638 2,221,245 Less accumulated depreciation and amortization (452,823 ) (373,977 ) Property and equipment, net $ 2,102,815 $ 1,847,268

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Summary of Long-Term Debt	Long-term debt and finance lease obligations: (in thousands) As of September 30, 2019 As of December 31, 2018 Fixed-rate debt and finance lease obligations due through 2029 (1) $ 215,839 $ 640,806 Variable-rate debt due through 2029 1,136,145 630,927 Total long-term debt and finance lease obligations, net of related costs 1,351,984 1,271,733 Less current maturities, net of related costs (1) 138,685 152,287 Long-term debt and finance lease obligations, net of current maturities and related costs $ 1,213,299 $ 1,119,446 Weighted average fixed-interest rate on debt 3.9 % 5.3 % Weighted average variable-interest rate on debt 4.8 % 4.2 %

Long-Term Debt Schedule of Matu

Long-Term Debt Schedule of Maturities (Tables)	9 Months Ended
	Sep. 30, 2019
Schedule of Maturities of Long-Term Debt [Abstract]
Schedule of Maturities of Long-term Debt	Maturities of long-term debt and finance lease obligations for the remainder of 2019 and for the next four years and thereafter, in the aggregate, are: remaining in 2019 - $33.0 million ; 2020 - $138.9 million ; 2021 - $133.4 million ; 2022 - $113.8 million ; 2023 - $100.9 million ; and $832.0 million thereafter.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value On a Recurring Basis	Financial instruments measured at fair value on a recurring basis: As of September 30, 2019 As of December 31, 2018 (in thousands) Total Level 1 Level 2 Total Level 1 Level 2 Cash equivalents Money market funds $ 65,014 $ 65,014 $ — $ 43,281 $ 43,281 $ — Commercial paper 5,731 — 5,731 29,138 — 29,138 Municipal debt securities 4,087 — 4,087 — — — Federal agency debt securities 124 — 124 — — — US Treasury bonds — — — 1,415 — 1,415 Total cash equivalents 74,956 65,014 9,942 73,834 43,281 30,553 Short-term Corporate debt securities 149,854 — 149,854 101,489 — 101,489 Commercial paper 142,656 — 142,656 180,846 — 180,846 Federal agency debt securities 11,510 — 11,510 11,887 — 11,887 Municipal debt securities 7,785 — 7,785 14,252 — 14,252 US Treasury bonds 3,017 — 3,017 5,990 — 5,990 Total short-term 314,822 — 314,822 314,464 — 314,464 Long-term Corporate debt securities 35,996 — 35,996 37,334 — 37,334 US Treasury bonds 3,061 — 3,061 2,901 — 2,901 Federal agency debt securities — — — 11,291 — 11,291 Total long-term 39,057 — 39,057 51,526 — 51,526 Total financial instruments $ 428,835 $ 65,014 $ 363,821 $ 439,824 $ 43,281 $ 396,543
Fair Value, Liabilities Measured on Recurring Basis	Carrying value and estimated fair value of long-term debt, including current maturities and without reduction for related costs are as follows: As of September 30, 2019 As of December 31, 2018 (in thousands) Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Hierarchy Level Non-publicly held debt $ 1,259,130 $ 1,053,911 $ 703,372 $ 619,379 3 Publicly held debt — — 450,463 451,026 2 Total long-term debt $ 1,259,130 $ 1,053,911 $ 1,153,835 $ 1,070,405

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Computation of Net Income Per Share, Basic and Diluted	The following table sets forth the computation of net income per share, on a basic and diluted basis, for the periods indicated (share count and dollar amounts other than per-share amounts in table are in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Basic: Net income $ 43,929 $ 15,147 $ 171,596 $ 120,356 Less net income allocated to participating securities (578 ) (194 ) (2,441 ) (1,602 ) Net income attributable to common stock $ 43,351 $ 14,953 $ 169,155 $ 118,754 Earnings per share, basic $ 2.70 $ 0.94 $ 10.55 $ 7.46 Weighted-average shares outstanding 16,037 15,957 16,037 15,929 Diluted: Net income $ 43,929 $ 15,147 $ 171,596 $ 120,356 Less net income allocated to participating securities (578 ) (194 ) (2,440 ) (1,601 ) Net income attributable to common stock $ 43,351 $ 14,953 $ 169,156 $ 118,755 Earnings per share, diluted $ 2.70 $ 0.94 $ 10.54 $ 7.45 Weighted-average shares outstanding 16,037 15,957 16,037 15,929 Dilutive effect of stock options and restricted stock 56 35 45 42 Adjusted weighted-average shares outstanding under treasury stock method 16,093 15,992 16,082 15,971 Participating securities excluded under two-class method (54 ) (30 ) (37 ) (33 ) Adjusted weighted-average shares outstanding under two-class method 16,039 15,962 16,045 15,938

Commitments and Contingencies P

Commitments and Contingencies Payments Related to Commitments to Purchase (Tables)	9 Months Ended
	Sep. 30, 2019
Payments Related to Commitments to Purchase [Abstract]
Long-term Purchase Commitment [Table Text Block]	The Company's contractual purchase commitments consist primarily of aircraft and engine acquisitions. The total future commitments are as follows: (in thousands) As of September 30, 2019 Remaining in 2019 $ 53,400 2020 157,900 2021 37,900 2022 21,000 Total commitments $ 270,200

Lease (Tables)

Lease (Tables)	9 Months Ended
	Sep. 30, 2019
Cash paid for lease [Abstract]
Lease, Cost [Table Text Block]	The components of lease costs recognized on the statements of income were as follows: Three Months Ended Nine Months Ended (in thousands) Classification on the Statements of Income September 30, 2019 September 30, 2019 Finance lease costs: Amortization of assets Depreciation and amortization $ 1,629 $ 4,888 Interest on lease liabilities Interest expense 1,306 3,978 Operating lease cost Station operations; Maintenance and repairs; Other operating expense 897 2,634 Variable lease cost Station operations; Maintenance and repairs; Other operating expense 663 1,672 Total lease cost $ 4,495 $ 13,172
Leases of Lessee Disclosure [Text Block]	The table below presents the lease-related assets and liabilities recorded on the balance sheet. As of (in thousands) Classification on the Balance Sheet September 30, 2019 Assets Operating lease assets Operating lease right-of-use assets, net $ 22,433 Finance lease assets Property and equipment, net 113,294 Total lease assets $ 135,727 Liabilities Current Operating Accrued liabilities $ 2,388 Finance Current maturities of long-term debt and finance lease obligations 7,582 Noncurrent Operating Other noncurrent liabilities 21,744 Finance Long-term debt and finance lease obligations 109,878 Total lease liabilities $ 141,592 Weighted-average remaining lease term Operating leases 9.4 years Finance leases 10.1 years Weighted-average discount rate Operating leases 4.3 % Finance leases 4.4 %
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	The table below presents supplemental cash flow information related to leases during the three and nine months ended September 30, 2019 . Three Months Ended Nine Months Ended (in thousands) September 30, 2019 September 30, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 725 $ 2,190 Operating cash flows for finance leases 1,306 3,978 Financing cash flows for finance leases 1,844 5,472
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	The table below indicates the future minimum payments of lease liabilities as of September 30, 2019 . (in thousands) Operating Leases Finance Leases Remaining in 2019 $ 726 $ 3,150 2020 3,566 12,600 2021 3,382 12,600 2022 3,361 11,095 2023 3,213 10,500 Thereafter 15,317 103,459 Total lease payments 29,565 153,404 Less imputed interest (5,433 ) (35,944 ) Total lease obligations 24,132 117,460 Less current obligations (2,388 ) (7,582 ) Long-term lease obligations $ 21,744 $ 109,878 The Company adopted the New Lease Standard on January 1, 2019 as noted above, and as required, the following disclosure is provided for periods prior to adoption. Future annual minimum lease payments as of December 31, 2018 were as follows: (in thousands) Operating Leases Finance Leases 2019 $ 8,102 $ 12,600 2020 6,031 12,600 2021 3,643 12,600 2022 1,630 11,095 2023 1,626 10,500 Thereafter 8,297 103,458 Total lease payments $ 29,329 162,853 Less imputed interest (39,922 ) Total lease obligations 122,931 Less current obligations (7,336 ) Long-term lease obligations $ 115,595

Operating Segments (Tables)

Operating Segments (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Selected information for the Company's segments and the reconciliation to the consolidated financial statement amounts are as follows: (in thousands) Airline Sunseeker Resort Other non- airline Consolidated Three Months Ended September 30, 2019 Operating revenue: Passenger $ 391,222 $ — $ — $ 391,222 Third party products 18,207 — — 18,207 Fixed fee contract 19,797 — — 19,797 Other 1,648 251 5,384 7,283 Operating income (loss) 77,335 (1,281 ) (3,938 ) 72,116 Interest expense, net 14,761 507 — 15,268 Depreciation and amortization 38,409 329 698 39,436 Capital expenditures 98,308 16,931 479 115,718 Three Months Ended September 30, 2018 Operating revenue: Passenger $ 355,100 $ — $ — $ 355,100 Third party products 15,921 — — 15,921 Fixed fee contract 14,791 — — 14,791 Other 4,611 94 2,592 7,297 Operating income (loss) 29,727 (1,136 ) (2,410 ) 26,181 Interest expense, net 11,884 — — 11,884 Depreciation and amortization 34,138 47 473 34,658 Capital expenditures 74,799 8,197 3,547 86,543 (in thousands) Airline Sunseeker Resort Other non- airline Consolidated Nine Months Ended September 30, 2019 Operating revenue: Passenger $ 1,265,978 $ — $ — $ 1,265,978 Third party products 53,557 — — 53,557 Fixed fee contract 42,859 — — 42,859 Other 3,578 1,526 12,394 17,498 Operating income (loss) 291,371 (4,199 ) (15,874 ) 271,298 Interest expense, net 43,906 1,143 — 45,049 Depreciation and amortization 110,528 811 2,773 114,112 Capital expenditures 305,356 33,502 11,329 350,187 Nine Months Ended September 30, 2018 Operating revenue: Passenger $ 1,157,443 $ — $ — $ 1,157,443 Third party products 44,045 — — 44,045 Fixed fee contract 33,000 — — 33,000 Other 14,808 94 5,943 20,845 Operating income (loss) 187,731 (1,582 ) (5,778 ) 180,371 Interest expense, net 33,929 — — 33,929 Depreciation and amortization 91,309 64 1,268 92,641 Capital expenditures 240,733 25,541 7,725 273,999 Total assets were as follows as of the dates indicated: (in thousands) September 30, 2019 December 31, 2018 Airline $ 2,689,869 $ 2,422,523 Sunseeker Resort 104,283 56,047 Other non-airline 40,328 20,098 Consolidated $ 2,834,480 $ 2,498,668

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Adjustments for New Accounting Pronouncements [Line Items]
Operating Lease, Right-of-Use Asset		$ 18,000
Operating Lease, Liability	$ 24,132	$ 19,100

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Passenger	$ 391,222	$ 355,100	$ 1,265,978	$ 1,157,443
Allegiant Air
Disaggregation of Revenue [Line Items]
Passenger	391,222	355,100	1,265,978	1,157,443
Allegiant Air | Scheduled Service Revenue
Disaggregation of Revenue [Line Items]
Passenger	200,233	202,796	672,690	677,061
Allegiant Air | Air-related revenue
Disaggregation of Revenue [Line Items]
Passenger	187,776	150,095	583,003	472,443
Allegiant Air | Co-brand Revenue
Disaggregation of Revenue [Line Items]
Passenger	$ 3,213	$ 2,209	$ 10,285	$ 7,939

Revenue Recognition Points Liab

Revenue Recognition Points Liability (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Points Liability [Abstract]
Points Liability Start of Period	$ 10,708	$ 8,903
Points awarded	14,308	10,872
Points redeemed	(10,285)	(7,939)
Contract with Customer, Liability	14,731	11,836
Points Liability	$ 10,600	$ 8,100

Revenue Recognition Passenger R

Revenue Recognition Passenger Revenue (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Revenue Recognition [Abstract]
Increase (Decrease) in Deferred Air Traffic Revenue	$ 210,100
Air traffic liability	$ 267,676	$ 212,230

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Capital Expenditures Incurred but Not yet Paid	$ 6,100	$ 3,800
Flight equipment, including pre-delivery deposits	2,168,557		$ 1,905,157
Computer hardware and software	158,720		140,385
Land and buildings/leasehold improvements	86,163		85,925
Other property and equipment	142,198		89,778
Total property and equipment	2,555,638		2,221,245
Less accumulated depreciation and amortization	452,823		373,977
Property and equipment, net	$ 2,102,815		$ 1,847,268

Long-Term Debt Components of Lo

Long-Term Debt Components of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Notes Payable	$ 1,259,130	$ 1,153,835
Secured Long-term Debt, Noncurrent	1,351,984	1,271,733
Less current maturities	138,685	152,287
Long-term debt and capital leases, net of current maturities and related costs	1,213,299	1,119,446
Weighted average fixed-interest rate on debt
Debt Instrument [Line Items]
Notes Payable	$ 215,839	$ 640,806
Long-term Debt, Weighted Average Interest Rate, at Point in Time	3.90%	5.30%
Weighted average variable-interest rate on debt
Debt Instrument [Line Items]
Notes Payable	$ 1,136,145	$ 630,927
Long-term Debt, Weighted Average Interest Rate, at Point in Time	4.80%	4.20%
Unsecured Debt | Weighted average fixed-interest rate on debt
Debt Instrument [Line Items]
Notes Payable		$ 428,000

Long-Term Debt (Details)

Long-Term Debt (Details)	1 Months Ended					3 Months Ended				9 Months Ended
	Sep. 30, 2019USD ($)Aircraftaircraft	Jul. 31, 2019USD ($)	Jun. 30, 2019USD ($)aircraft	Mar. 31, 2019USD ($)aircraft	Feb. 28, 2019USD ($)	Sep. 30, 2019USD ($)Aircraft	Jun. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Sep. 30, 2019USD ($)Aircraft	Sep. 30, 2018USD ($)	Feb. 01, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2016USD ($)
Capital Leased Assets, Number of Units | Aircraft	5					5				5
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year	$ 33,000,000					$ 33,000,000				$ 33,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	138,900,000					138,900,000				138,900,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	133,400,000					133,400,000				133,400,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	113,800,000					113,800,000				113,800,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	100,900,000					100,900,000				100,900,000
Long-term Debt, Maturities, Repayments of Principal after Year Five	832,000,000					832,000,000				832,000,000
Debt Instrument, Face Amount			$ 63,400,000				$ 63,400,000					$ 450,000,000
Secured Long-term Debt, Noncurrent	1,351,984,000					1,351,984,000				1,351,984,000			$ 1,271,733,000
Line of Credit Facility, Maximum Borrowing Capacity				$ 175,000,000
Finance Lease, Right-of-Use Asset, Amortization						1,629,000				4,888,000
Line of Credit Facility, Fair Value of Amount Outstanding	0					0				0
Repayments of Unsecured Debt		$ 102,100,000
Gain (Loss) on Extinguishment of Debt					$ 3,700,000	0		$ 0		3,677,000	$ 0
Debt, Number of Debt Instruments			6				6
Debt Instrument, Periodic Payment, Principal					1,100,000
Consolidated Variable Interest Entity
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities				44,000,000
Variable Interest Entity, Consolidated, Carrying Amount, Assets				$ 39,100,000
Debt, Weighted Average Interest Rate				3.80%
Senior Secured Revolving Credit Facility
Line of Credit Facility, Maximum Borrowing Capacity									$ 81,000,000
Line of Credit Facility, Fair Value of Amount Outstanding	$ 0					$ 0				$ 0
Debt Instrument, Term									24 months
Unsecured Debt
Unsecured Long-term Debt, Noncurrent														$ 450,000,000
Debt Instrument, Interest Rate, Stated Percentage														5.50%
Repayments of Unsecured Debt					$ 347,900,000
Airbus A320 Aircraft Series | Consolidated Variable Interest Entity
Number Of Aircrafts Included As Collateral | aircraft				1
Loan Due June 2024
Debt Instrument, Face Amount			$ 213,000,000				$ 213,000,000
Number Of Aircrafts Included As Collateral | aircraft			23
Debt Instrument, Term			5 years
Minimum
Debt Instrument, Term							7 years
Maximum
Debt Instrument, Term							10 years
Senior Secured Revolving Credit Facility
Number Of Aircrafts Included As Collateral | aircraft	4
Term Loan Due February 2024
Debt Instrument, Term					5 years

Long-Term Debt Schedule of Ma_2

Long-Term Debt Schedule of Maturities of Long-Term Debt (Details)	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)aircraft	Feb. 28, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Gain (Loss) on Extinguishment of Debt		$ (3,700,000)	$ 0	$ 0	$ (3,677,000)	$ 0
Line of Credit Facility, Maximum Borrowing Capacity							$ 175,000,000
Line of Credit Facility, Fair Value of Amount Outstanding	$ 0		0		0
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year	33,000,000		33,000,000		33,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	138,900,000		138,900,000		138,900,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	133,400,000		133,400,000		133,400,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	113,800,000		113,800,000		113,800,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	100,900,000		100,900,000		100,900,000
Long-term Debt, Maturities, Repayments of Principal after Year Five	832,000,000		832,000,000		832,000,000
Long-term Debt, Fair Value	$ 1,351,984,000		$ 1,351,984,000		$ 1,351,984,000			$ 1,271,733,000
Term Loan Due February 2024
Debt Instrument [Line Items]
Debt Instrument, Term		5 years
Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Number Of Aircrafts Included As Collateral | aircraft	4

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Available-for-sale Securities	$ 428,835	$ 439,824
Fair Value, Inputs, Level 1
Available-for-sale Securities	65,014	43,281
Fair Value, Inputs, Level 2
Available-for-sale Securities	363,821	396,543
Short-term Investments
Available-for-sale Securities	314,822	314,464
Short-term Investments | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Fair Value, Inputs, Level 2
Available-for-sale Securities	314,822	314,464
Short-term Investments | Commercial paper
Available-for-sale Securities	142,656	180,846
Short-term Investments | Commercial paper | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Commercial paper | Fair Value, Inputs, Level 2
Available-for-sale Securities	142,656	180,846
Short-term Investments | Municipal debt securities
Available-for-sale Securities	7,785	14,252
Short-term Investments | Municipal debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Municipal debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	7,785	14,252
Short-term Investments | Federal agency debt securities
Available-for-sale Securities	11,510	11,887
Short-term Investments | Federal agency debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Federal agency debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	11,510	11,887
Short-term Investments | Corporate debt securities
Available-for-sale Securities	149,854	101,489
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	149,854	101,489
Short-term Investments | US Treasury Bond Securities
Available-for-sale Securities	3,017	5,990
Short-term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	3,017	5,990
Long Term Investments
Available-for-sale Securities	39,057	51,526
Long Term Investments | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Long Term Investments | Fair Value, Inputs, Level 2
Available-for-sale Securities	39,057	51,526
Long Term Investments | Federal agency debt securities
Available-for-sale Securities	0	11,291
Long Term Investments | Federal agency debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Long Term Investments | Federal agency debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	0	11,291
Long Term Investments | Corporate debt securities
Available-for-sale Securities	35,996	37,334
Long Term Investments | Corporate debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Long Term Investments | Corporate debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	35,996	37,334
Long Term Investments | US Treasury Bond Securities
Available-for-sale Securities	3,061	2,901
Long Term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Long Term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	3,061	2,901
Cash Equivalents
Cash Equivalents	74,956	73,834
Cash Equivalents | Fair Value, Inputs, Level 1
Cash Equivalents	65,014	43,281
Cash Equivalents | Fair Value, Inputs, Level 2
Cash Equivalents	9,942	30,553
Cash Equivalents | Money Market Funds
Cash Equivalents	65,014	43,281
Cash Equivalents | Money Market Funds | Fair Value, Inputs, Level 1
Cash Equivalents	65,014	43,281
Cash Equivalents | Money Market Funds | Fair Value, Inputs, Level 2
Cash Equivalents	0	0
Cash Equivalents | Commercial paper
Cash Equivalents	5,731	29,138
Cash Equivalents | Commercial paper | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Commercial paper | Fair Value, Inputs, Level 2
Cash Equivalents	5,731	29,138
Cash Equivalents | Municipal debt securities
Cash Equivalents	4,087	0
Cash Equivalents | Municipal debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Municipal debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	4,087	0
Cash Equivalents | Federal agency debt securities
Cash Equivalents	124	0
Cash Equivalents | Federal agency debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Federal agency debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	124	0
Cash Equivalents | US Treasury Bond Securities
Cash Equivalents	0	1,415
Cash Equivalents | US Treasury Bond Securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | US Treasury Bond Securities | Fair Value, Inputs, Level 2
Cash Equivalents	$ 0	$ 1,415

Fair Value Measurements Estimat

Fair Value Measurements Estimated Fair Value of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	$ 1,351,984	$ 1,271,733
Notes Payable	1,259,130	1,153,835
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	1,053,911	1,070,405
Publicly Held Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	0	450,463
Publicly Held Debt | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	0	451,026
Non-Publicly Held Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	1,259,130	703,372
Non-Publicly Held Debt | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	$ 1,053,911	$ 619,379

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic:
Net income attributable to Allegiant Travel Company (in Dollars)	$ 43,929	$ 15,147	$ 171,596	$ 120,356
Less: Net income allocated to participating securities (in Dollars)	(578)	(194)	(2,441)	(1,602)
Net income attributable to common stock (in Dollars)	$ 43,351	$ 14,953	$ 169,155	$ 118,754
Net income per share, basic (in Dollars per share)	$ 2.70	$ 0.94	$ 10.55	$ 7.46
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	$ (578)	$ (194)	$ (2,440)	$ (1,601)
Net Income (Loss) Available to Common Stockholders, Diluted	$ 43,351	$ 14,953	$ 169,156	$ 118,755
Diluted earnings per share	$ 2.70	$ 0.94	$ 10.54	$ 7.45
Weighted-average shares outstanding	16,037,000	15,957,000	16,037,000	15,929,000
Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	56,000	35,000	45,000	42,000
Adjusted weighted-average shares outstanding under treasury stock method	16,093,000	15,992,000	16,082,000	15,971,000
Participating securities excluded under two-class method	(54,000)	(30,000)	(37,000)	(33,000)
Two-Class Method, Weighted Average Number of Shares Outstanding, Diluted	16,039,000	15,962,000	16,045,000	15,938,000

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Sep. 30, 2019USD ($)aircraft
Long-term Purchase Commitment [Line Items]
Number Of Aircraft Committed To Purchase | aircraft	14
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	$ 53,400
Unrecorded Unconditional Purchase Obligation, Due within Two Years	157,900
Unrecorded Unconditional Purchase Obligation, Due within Three Years	37,900
Unrecorded Unconditional Purchase Obligation, Due within Four Years	21,000
Unrecorded Unconditional Purchase Obligation	$ 270,200

Commitments and Contingencies_2

Commitments and Contingencies Payments Related to Commitments to Purchase (Details) $ in Thousands	Sep. 30, 2019USD ($)
Payments Related to Commitments to Purchase [Abstract]
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	$ 53,400
Unrecorded Unconditional Purchase Obligation, Due within Two Years	157,900
Unrecorded Unconditional Purchase Obligation, Due within Three Years	37,900
Unrecorded Unconditional Purchase Obligation, Due within Four Years	21,000
Unrecorded Unconditional Purchase Obligation	$ 270,200

Lease (Details)

Lease (Details) $ in Thousands	Sep. 30, 2019USD ($)Aircraft	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)
Leases [Abstract]
Capital Leased Assets, Number of Units | Aircraft	5
Finance Lease, Weighted Average Remaining Lease Term	9 years 4 months 20 days
Operating Lease, Liability	$ 24,132	$ 19,100
Operating lease right-of-use assets, net	22,433		$ 0
Finance Lease, Right-of-Use Asset	113,294
Total Right-of-Use Asset	135,727
Operating Lease, Liability, Current	2,388
Finance Lease, Liability, Current	7,582
Operating Lease, Liability, Noncurrent	21,744
Finance Lease, Liability, Noncurrent	109,878
Total Lease Liability	$ 141,592
Operating Lease, Weighted Average Discount Rate, Percent	4.30%
Finance Lease, Weighted Average Discount Rate, Percent	4.40%
Operating Lease, Weighted Average Remaining Lease Term	10 years 1 month 6 days

Lease Cash paid for lease (Deta

Lease Cash paid for lease (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Cash paid for lease [Abstract]
Operating Lease, Payments	$ 725	$ 2,190
Finance Lease, Interest Payment on Liability	1,306	3,978
Finance Lease, Principal Payments	$ 1,844	$ 5,472

Lease Scheduled Lease Payments

Lease Scheduled Lease Payments Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Scheduled Lease Payment Commitments [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 726
Finance Lease, Liability, Payments, Remainder of Fiscal Year	3,150
Lessee, Operating Lease, Liability, Payments, Due Year Two	3,566
Finance Lease, Liability, Payments, Due Year Two	12,600
Lessee, Operating Lease, Liability, Payments, Due Year Three	3,382
Finance Lease, Liability, Payments, Due Year Three	12,600
Lessee, Operating Lease, Liability, Payments, Due Year Four	3,361
Finance Lease, Liability, Payments, Due Year Four	11,095
Lessee, Operating Lease, Liability, Payments, Due Year Five	3,213
Finance Lease, Liability, Payments, Due Year Five	10,500
Lessee, Operating Lease, Liability, Payments, Due after Year Five	15,317
Finance Lease, Liability, Payments, Due after Year Five	103,459
Lessee, Operating Lease, Liability, Payments, Due	29,565
Finance Lease, Liability, Payment, Due	153,404
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(5,433)
Finance Lease, Liability, Undiscounted Excess Amount	(35,944)
Operating Lease, Liability	24,132	$ 19,100
Finance Lease, Liability	117,460
Operating Lease, Liability, Current	(2,388)
Finance Lease, Liability, Current	(7,582)
Operating Lease, Liability, Noncurrent	21,744
Finance Lease, Liability, Noncurrent	$ 109,878
Operating Leases, Future Minimum Payments Due, Next Twelve Months			$ 8,102
Capital Leases, Future Minimum Payments Due, Next Twelve Months			12,600
Operating Leases, Future Minimum Payments, Due in Two Years			6,031
Capital Leases, Future Minimum Payments Due in Two Years			12,600
Operating Leases, Future Minimum Payments, Due in Three Years			3,643
Capital Leases, Future Minimum Payments Due in Three Years			12,600
Operating Leases, Future Minimum Payments, Due in Four Years			1,630
Capital Leases, Future Minimum Payments Due in Four Years			11,095
Operating Leases, Future Minimum Payments, Due in Five Years			1,626
Capital Leases, Future Minimum Payments Due in Five Years			10,500
Operating Leases, Future Minimum Payments, Due Thereafter			8,297
Capital Leases, Future Minimum Payments, Due in Rolling after Year Five			103,458
Commitments, Fair Value Disclosure			29,329
Capital Leases, Future Minimum Payments Due			162,853
Capital Leases, Future Minimum Payments, Interest Included in Payments			(39,922)
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments			122,931
Capital Lease Obligations, Current			(7,336)
Capital Lease Obligations, Noncurrent			$ 115,595

Lease Lease Costs (Details)

Lease Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Finance Lease, Right-of-Use Asset, Amortization	$ 1,629	$ 4,888
Finance Lease, Interest Payment on Liability	1,306	3,978
Operating Lease, Cost	897	2,634
Variable Lease, Cost	663	1,672
Lease, Cost	$ 4,495	$ 13,172

Operating Segments (Details)

Operating Segments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments			3
Passenger	$ 391,222	$ 355,100	$ 1,265,978	$ 1,157,443
Third party products	18,207	15,921	53,557	44,045
Fixed fee contracts	19,797	14,791	42,859	33,000
Other	7,283	7,297	17,498	20,845
Operating Income (Loss)	72,116	26,181	271,298	180,371
Interest Revenue (Expense), Net	15,268	11,884	45,049	33,929
Depreciation and amortization	39,436	34,658	114,112	92,641
Payments to Acquire Productive Assets	115,718	86,543	350,187	273,999
Increase (Decrease) in Assets Held-for-sale	5,500
Assets	2,834,480		2,834,480		$ 2,498,668
Allegiant Air
Segment Reporting Information [Line Items]
Passenger	391,222	355,100	1,265,978	1,157,443
Third party products	18,207	15,921	53,557	44,045
Fixed fee contracts	19,797	14,791	42,859	33,000
Other	1,648	4,611	3,578	14,808
Operating Income (Loss)	77,335	29,727	291,371	187,731
Interest Revenue (Expense), Net	14,761	11,884	43,906	33,929
Depreciation and amortization	38,409	34,138	110,528	91,309
Payments to Acquire Productive Assets	98,308	74,799	305,356	240,733
Assets	2,689,869		2,689,869		2,422,523
Sunseeker Resorts
Segment Reporting Information [Line Items]
Other	251	94	1,526	94
Operating Income (Loss)	(1,281)	(1,136)	(4,199)	(1,582)
Interest Revenue (Expense), Net	507	0	1,143	0
Depreciation and amortization	329	47	811	64
Payments to Acquire Productive Assets	16,931	8,197	33,502	25,541
Assets	104,283		104,283		56,047
Other
Segment Reporting Information [Line Items]
Other	5,384	2,592	12,394	5,943
Operating Income (Loss)	(3,938)	(2,410)	(15,874)	(5,778)
Interest Revenue (Expense), Net	0	0	0	0
Depreciation and amortization	698	473	2,773	1,268
Payments to Acquire Productive Assets	479	$ 3,547	11,329	$ 7,725
Assets	$ 40,328		$ 40,328		$ 20,098