Allegiant Travel (ALGT) 10-Q 10 Nov 14 2014 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2014	Nov. 01, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'Allegiant Travel CO	'
Document Type	'10-Q	'
Current Fiscal Year End Date	'--12-31	'
Entity Common Stock, Shares Outstanding	'	17,484,393
Amendment Flag	'false	'
Entity Central Index Key	'0001362468	'
Entity Current Reporting Status	'Yes	'
Entity Voluntary Filers	'No	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Well Known Seasoned Issuer	'Yes	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'

Consolidated_Balance_Sheets_Cu

Consolidated Balance Sheets (Current Period Unaudited) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$86,197	$97,711
Restricted cash	17,682	10,531
Short-term investments	272,555	253,378
Accounts receivable	16,508	16,857
Expendable parts, supplies and fuel, net of allowance	16,402	19,428
Prepaid expenses	24,215	26,643
Deferred income taxes	3,003	4,206
Other current assets	3,751	1,167
Total current assets	440,313	429,921
Property and equipment, net	717,058	451,584
Restricted cash, net of current portion	305	305
Long-term investments	99,143	36,037
Investment in and advances to unconsolidated affiliates, net	1,703	1,655
Deposits and other assets	11,382	10,689
Total assets	1,269,904	930,191
Current liabilities:	'	'
Current maturities of long-term debt	51,895	20,237
Accounts payable	18,678	15,823
Accrued liabilities	60,260	87,203
Air traffic liability	195,128	167,388
Total current liabilities	325,961	290,651
Long-term debt and other long-term liabilities: [Abstract]	'	'
Long-term debt, net of current maturities	554,421	214,063
Deferred income taxes	48,289	48,160
Total liabilities	928,671	552,874
Stockholders' equity:	'	'
Common stock, par value $.001, 100,000,000 shares authorized; 22,176,778 and 22,036,893 shares issued; 17,484,393 and 18,544,248 shares outstanding, as of September 30, 2014 and December 31, 2013, respectively	22	22
Treasury stock, at cost, 4,692,385 and 3,492,645 shares at September 30, 2014 and December 31, 2013, respectively	-315,614	-186,291
Additional paid in capital	220,229	209,213
Accumulated other comprehensive gain (loss), net	672	-12
Retained earnings	434,690	352,811
Total Allegiant Travel Company stockholders' equity	339,999	375,743
Noncontrolling interest	1,234	1,574
Total equity	341,233	377,317
Total liabilities and stockholders' equity	$1,269,904	$930,191

Consolidated_Balance_Sheets_Cu1

Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Allowance for obsolescence (in dollars)	$2,658	$1,702
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	22,176,778	22,036,893
Common stock, shares outstanding	17,484,393	18,544,248
Treasury stock, shares	4,692,385	3,492,645

Consolidated_Statements_of_Inc

Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
OPERATING REVENUE:	'	'	'	'
Scheduled service revenue	$166,893	$148,466	$559,587	$493,700
Ancillary revenue:	'	'	'	'
Air-related charges	77,198	66,577	248,432	219,904
Third party products, net	8,051	8,646	28,338	29,733
Total ancillary revenue	85,249	75,223	276,770	249,637
Fixed fee contract revenue	4,899	3,985	10,508	12,267
Other revenue	7,988	1,200	11,229	2,075
Total operating revenue	265,029	228,874	858,094	757,679
OPERATING EXPENSES:	'	'	'	'
Aircraft fuel	94,864	89,195	308,308	294,762
Salary and benefits	52,109	38,135	145,845	118,951
Station operations	21,064	19,114	63,453	58,670
Maintenance and repairs	22,562	18,310	64,590	56,773
Sales and marketing	7,808	4,514	22,269	15,727
Aircraft lease rentals	1,565	2,025	12,897	3,693
Depreciation and amortization	22,174	17,106	60,355	51,890
Other	14,016	11,243	37,826	32,758
Total operating expenses	236,162	199,642	715,543	633,224
OPERATING INCOME	28,867	29,232	142,551	124,455
OTHER (INCOME) EXPENSE:	'	'	'	'
Earnings from unconsolidated affiliates, net	-101	-214	-173	-384
Interest income	-106	-328	-545	-806
Interest expense	7,097	2,257	13,817	6,739
Total other expense	6,890	1,715	13,099	5,549
INCOME BEFORE INCOME TAXES	21,977	27,517	129,452	118,906
PROVISION FOR INCOME TAXES	7,866	10,520	47,900	44,391
NET INCOME	14,111	16,997	81,552	74,515
Net loss attributable to noncontrolling interest	-61	-109	-340	-283
NET INCOME ATTRIBUTABLE TO ALLEGIANT TRAVEL COMPANY	$14,172	$17,106	$81,892	$74,798
Earnings per share to common stockholders:	'	'	'	'
Basic (in Dollars per share)	$0.80	$0.91	$4.56	$3.92
Diluted (in Dollars per share)	$0.80	$0.91	$4.54	$3.90
Weighted average shares outstanding used in computing earnings per share to common stockholders:	'	'	'	'
Basic (in Shares)	17,605	18,629	17,848	18,925
Diluted (in Shares)	17,704	18,794	17,912	19,042

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$14,111	$16,997	$81,552	$74,515
Other comprehensive income:	'	'	'	'
Unrealized (loss) gain on available-for-sale securities, net	-202	63	-139	158
Income tax expense related to unrealized gain or loss on derivative activities	66	-23	54	-59
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	959	0	1,221	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	-343	0	-452	0
Total other comprehensive income	480	40	684	99
Total comprehensive income	14,591	17,037	82,236	74,614
Net loss attributable to noncontrolling interest	-61	-109	-340	-283
Comprehensive income attributable to Allegiant Travel Company	$14,652	$17,146	$82,576	$74,897

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
OPERATING ACTIVITIES:	'	'
Net income	$81,552	$74,515
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	60,355	51,890
Loss on aircraft and other equipment disposals	3,967	4,967
Provision for obsolescence of expendable parts, supplies and fuel	956	540
Amortization of deferred financing costs and original issue discount	-2,209	481
Stock-based compensation expense	13,813	7,930
Deferred income taxes	1,332	-980
Excess tax benefits from stock-based compensation	-3,339	-1,628
Changes in certain assets and liabilities:	'	'
Restricted cash	-7,151	-3,803
Accounts receivable	349	2,046
Expendable parts, supplies and fuel	2,070	-3,182
Prepaid expenses	4,928	2,134
Other current assets	-3,741	2,911
Accounts payable	6,194	-1,167
Accrued liabilities	8,338	1,193
Air traffic liability	27,740	12,585
Net cash provided by operating activities	195,154	150,432
INVESTING ACTIVITIES:	'	'
Purchase of investment securities	-285,918	-226,763
Proceeds from maturities and sale of investment securities	204,306	219,387
Purchase of property and equipment, including pre-delivery deposits	-188,131	-161,560
Interest during refurbishment of aircraft	0	-123
Proceeds from sale of property and equipment	295	494
Investment in unconsolidated affiliates, net	-48	-2,310
Change in deposits and other assets	506	10,224
Net cash used in investing activities	-268,990	-160,651
FINANCING ACTIVITIES:	'	'
Cash dividends paid to shareholders	-41,787	0
Excess tax benefits from stock-based compensation	3,339	1,628
Proceeds from exercise of stock options and stock-settled SARs	370	2,041
Proceeds from the issuance of long-term debt	385,300	48,000
Proceeds from sale of ownership interest in subsidiary	0	1,400
Repurchase of common stock	-129,323	-79,990
Principal payments on long-term debt	-155,577	-19,225
Payments for deferred financing costs	0	-204
Net cash provided by (used in) financing activities	62,322	-46,350
Net change in cash and cash equivalents	-11,514	-56,569
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	97,711	89,557
CASH AND CASH EQUIVALENTS AT END OF PERIOD	86,197	32,988
Non- cash transactions:	'	'
Assets acquired in sale of ownership interest in subsidiary	0	473
Notes Assumed	141,960	0
Noncash or Part Noncash Divestiture, Amount of Consideration Received	$0	$1,225

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
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. Investments in affiliates in which the Company’s ownership interest ranges from 20 to 50 percent and in which the Company has the ability to exercise significant influence over operating and financial policies are accounted for under the equity method. 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 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 condensed or 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, 2013, filed with the Securities and Exchange Commission.
	Use of estimates
	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 could differ from these estimates.
	The interim results reflected in the unaudited consolidated financial statements are not necessarily indicative of the results that may be expected for other interim periods or for the full year.
	Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board ("FASB") issued new guidance related to reporting discontinued operations. This new standard raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. The new standard is effective for fiscal years beginning on or after December 15, 2014. Early adoption is permitted but only for disposals that have not been reported in financial statements previously issued. The Company is evaluating the impact, if any, of adopting this new accounting standard on its financial statements.
	In May 2014, the FASB issued new accounting guidance related to revenue recognition. This new standard will replace all current U.S. GAAP guidance on this topic and eliminate all industry-specific guidance. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised 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. This guidance will be effective for the Company beginning January 1, 2017 and at that time, can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. The Company is evaluating the impact of adopting this new accounting standard on its financial statements.

Investment_Securities

Investment Securities	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Investment Securities	'
	Investment Securities
	The Company’s investments in marketable securities are classified as available-for-sale and are reported at fair market value with the net unrealized gain or loss reported as a component of accumulated other comprehensive income ("AOCI") in stockholders’ equity. Excluded from the table below is the change in fair value attributable to the foreign currency risk being hedged. Refer to Note 7 - Derivative Instruments for additional information related to the Company's foreign currency hedge. Investment securities are classified as cash equivalents, short-term investments and long-term investments based on maturity date. Cash equivalents have maturities of three months or less and short-term investments have maturities of greater than three months but equal to or less than one year and long-term investments are those with a maturity date greater than one year. Investment securities consisted of the following:
		As of September 30, 2014									As of December 31, 2013
				Gross Unrealized									Gross Unrealized
		Cost		Gains		(Losses)			Market Value		Cost		Gains		(Losses)			Market Value
	Money market funds	$	35,795	$	—	$	—		$	35,795	$	20,172	$	—	$	—		$	20,172
	Certificates of deposit	10,038		3		—			10,041		—		—		—			—
	Commercial paper	66,956		6		(10		)	66,952		75,905		8		(2		)	75,911
	Municipal debt securities	137,936		30		(3		)	137,963		181,870		17		(19		)	181,868
	Government debt securities	28,992		—		(29		)	28,963		10,008		—		—			10,008
	Corporate debt securities	141,153		1		(99		)	141,055		45,150		—		(16		)	45,134
	Federal agency debt securities	$	4,709	$	1	$	—		$	4,710	$	—	$	—	$	—		$	—
	Total	$	425,579	$	41	$	(141	)	$	425,479	$	333,105	$	25	$	(37	)	$	333,093
	The amortized cost of investment securities sold is determined by the specific identification method with any realized gains or losses reflected in other (income) expense. The Company had minimal realized gains for the nine months ended September 30, 2014 and 2013.

Property_and_Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment Disclosure	'
	Property and Equipment
	As of September 30, 2014, the Company owned 53 MD-80 aircraft, six Boeing 757-200 aircraft, seven Airbus A320 aircraft and 15 Airbus A319 aircraft, which include 12 Airbus A319 aircraft on lease to a third party. The Airbus A320 aircraft and Airbus A319 aircraft are sometimes referred to collectively as Airbus A320 series aircraft.
	Property and equipment consist of the following:
		As of September 30, 2014			As of December 31, 2013
	Flight equipment	$	936,462		$	629,715
	Ground property and equipment	90,065			73,638
	Total property and equipment	1,026,527			703,353
	Less accumulated depreciation and amortization	(309,469		)	(251,769		)
	Property and equipment, net	$	717,058		$	451,584
	In August 2014, the Company terminated the existing lease agreements and agreed to purchase eight Airbus A320 series aircraft subject to previously executed lease agreements. Concurrently with the execution of the agreement, the Company closed on the purchase of two of these aircraft which were previously on lease to the Company and were part of the Company’s operating fleet. The Company expects to take delivery of the remaining aircraft between December 2014 and December 2015. The financial impact of this transaction is reflected in the table above for the two purchased aircraft and in the contractual obligations table included in Note 10 - Commitments and Contingencies.
	In June 2014, the Company entered into separate agreements to acquire the ownership interests in 12 special purpose companies each owning one Airbus A320 series aircraft currently on lease to a European carrier until 2018. The purchase price for the special purpose companies was approximately $236.1 million, of which approximately $142.0 million was by assumption of debt secured by the aircraft with the remaining balance funded by cash. Refer to Note 4 - Long Term Debt for details on the assumed notes payable.
	The Company performed a fair value assessment of the assumed debt and the in-place leases and determined both to be at fair value. Upon expiration of the current leases in 2018, the Company intends to bring these aircraft into its operating fleet. Currently, the Company recognizes lease revenue and incurs minimal administrative costs to maintain the leases during the term these Airbus A320 series aircraft are under lease. Lease revenue and administrative costs related to this transaction are reflected in the Company's results of operations. Additionally, interest expense and depreciation expense related to the assumed notes payable and asset ownership of the acquired Airbus A320 series aircraft since their acquisition in June 2014 are reflected in the Company’s results of operations.
	The following table summarizes the Company's total aircraft fleet as of September 30, 2014:
	Aircraft Type		Owned (1)		Seating Capacity (per aircraft)			Average Age in Years
	MD-88/83		53		166			24.8
	B757-200		6		215			21.6
	A319 (2)		15		156			10
	A320		7		177			14
	Total aircraft		81
	-1	Two of the Company's owned Airbus A319 aircraft are unencumbered. Refer to Note 4 - Long-Term Debt for further information on the Company's notes payable.
	-2	Of the 15 Airbus A319 aircraft at September 30, 2014, three Airbus A319 aircraft are in revenue service and included in the Company's operating fleet and 12 Airbus A319 aircraft currently are on lease to a European carrier until 2018.

LongTerm_Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	Long-Term Debt
	Long-term debt consisted of the following:
		As of September 30, 2014		As of December 31, 2013
	5.50% Senior Notes, due July 2019	$	300,000	$	—
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due November 2018	135,995		—
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	43,302		48,000
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	41,053		—
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	39,110		45,775
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	37,108		—
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,748		9,953
	Senior secured term loan facility, interest at LIBOR plus 4.25% with LIBOR floor of 1.5%, due March 2017	—		121,230
	Note payable, secured by aircraft, interest at 4.65%, due July 2016	—		9,342
	Total long-term debt	606,316		234,300
	Less current maturities	51,895		20,237
	Long-term debt, net of current maturities	$	554,421	$	214,063
	Maturities of long-term debt, as of September 30, 2014, for the remainder of 2014 and for the next four years and thereafter, in aggregate, are:
		September 30, 2014
	2014	$	13,200
	2015	53,879
	2016	55,554
	2017	57,323
	2018	112,601
	Thereafter	313,759
	Total	$	606,316
	General Unsecured Senior Notes
	In June 2014, the Company completed an offering of $300.0 million aggregate principal amount of senior unsecured obligations (the "Notes") which will mature in July 2019. The Notes constitute general unsecured senior obligations of the Company and rank equally in right of payment with all existing and future senior unsecured indebtedness and liabilities (including trade payables) of the Company. The Notes are effectively junior to the Company’s existing and future secured indebtedness. The Notes are guaranteed by all of the Company’s wholly-owned domestic subsidiaries and rank equally in right of payment with all existing and future unsecured indebtedness and liabilities (including trade payables) of the Company’s guarantor subsidiaries, but effectively junior to the guarantors’ existing and future secured indebtedness.
	The Notes bear interest at a rate of 5.50 percent per year, payable in cash semi-annually, on January 15 and July 15 of each year, commencing on January 15, 2015, and will mature on July 15, 2019.
	At any time, the Company may redeem the Notes, in whole or in part, at a price equal to 100% of the principal amount of the Notes, plus accrued and unpaid interest, plus a “make-whole premium”. The occurrence of specific kinds of changes in control will be a triggering event requiring the Company to offer to purchase from the holders all or a portion of the Notes at a price equal to 101% of the principal amount, together with accrued and unpaid interest, if any, to the date of purchase.
	The indenture pursuant to which the Notes were issued includes operating and financial restrictions on the Company. These restrictions limit or restrict, among other things, the Company’s ability and the ability of its restricted subsidiaries to (i) incur additional indebtedness; (ii) incur liens; (iii) make restricted payments (including paying dividends on, redeeming, repurchasing or retiring capital stock); (iv) make investments; and (v) consolidate, merge or sell all or substantially all of its assets. These covenants are subject to various exceptions and qualifications under the terms of the indenture.
	Other
	In June 2014, the Company assumed $142.0 million of debt in connection with the acquisition of 12 separate special purpose companies, each owning one Airbus A320 series aircraft. The notes payable assumed bear interest at LIBOR plus 3.08 percent and are payable in monthly installments through November 2018 when a balloon payment is due.
	In May 2014, the Company borrowed $40.0 million secured by six Boeing 757-200 aircraft. The notes payable bear interest at LIBOR plus 2.95 percent and are payable in monthly installments through May 2018 when a balloon payment is due.
	In April 2014, the Company borrowed $45.3 million under a loan agreement secured by 53 MD-80 aircraft. The note payable issued under the loan agreement bears interest at LIBOR plus 2.95 percent and is payable in monthly installments through April 2018 when a balloon payment is due.
	In September 2013, the Company borrowed $48.0 million under a modified loan agreement secured by four Airbus A320 series aircraft. The notes payable issued under the modified loan agreement bear interest at 3.99 percent per annum and are payable in monthly installments through October 2018.
	In October 2013, the Company borrowed $10.0 million under a loan agreement secured by real estate now used as the Company's headquarter offices. The note payable issued under the loan agreement bears interest at 2.86 percent per annum and is payable in monthly installments through October 2018 when a balloon payment of $8.5 million is due.
	In November 2013, the Company borrowed $48.0 million under a loan agreement secured by four Airbus A320 series aircraft. The notes payable issued under the loan agreement bear interest at LIBOR plus 2.46 percent per annum and are payable in monthly installments through November 2019 when a balloon payment is due.
	In the second quarter 2014, the Company prepaid in full the $8.5 million balance owed on its note payable secured by two Boeing 757-200 aircraft originally due in July 2016.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Stockholders' Equity	'
	Stockholders’ Equity
	The Company is authorized by the Board of Directors to acquire the Company's stock through open market purchases under its share repurchase program. During the nine months ended September 30, 2014, the Company repurchased 953,309 shares through open market purchases at an average cost of $103.44 per share for a total expenditure of $98,606. In addition to open market purchases during the nine months ended September 30, 2014, the Company repurchased shares through private transactions totaling 246,431 shares at current market prices. Refer to Part II Item 2 - Unregistered Sales of Equity Securities and Use of Proceeds for detail on these transactions. Open market and private repurchases bring total repurchases for the first nine months of 2014 to 1,199,740 shares for a total expenditure of $129,323. During the nine months ended September 30, 2013, the Company repurchased 880,991 shares through open market purchases at an average price of $85.64 per share for a total expenditure of $75,449.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
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 to sell 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 as follows:
	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
	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 certificates of deposit, commercial paper, municipal debt securities, government debt securities, federal agency debt securities, 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.
	For those assets classified as Level 2 that are not in active markets, the Company obtained fair value from pricing sources using quoted market prices for identical or comparable instruments and based on pricing models which include all significant observable inputs, including 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.
	Derivative Financial Instruments
	The fair value of the Company's derivative instrument is determined using standard valuation models. The significant inputs used in these models are readily available in public markets or can be derived from observable market transactions and therefore have been classified as Level 2. Inputs used in these standard valuation models for derivative instruments include the applicable exchange and interest rates.
	Assets measured at fair value on a recurring basis at September 30, 2014 and December 31, 2013 were as follows:
						Fair Value Measurements at Reporting Date Using
	Description		September 30, 2014			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	35,795		$	35,795		$	—	$	—
	Commercial paper		9,999			—			9,999		—
	Municipal debt securities		7,283			—			7,283		—
	Corporate debt securities		704			—			704		—
	Total cash equivalents		53,781			35,795			17,986		—
	Short-term investments
	Municipal debt securities		122,204			—			122,204		—
	Corporate debt securities		78,647			—			78,647		—
	Commercial paper		56,953			—			56,953		—
	Certificates of deposit		10,041			—			10,041		—
	Federal agency debt securities		4,710			—			4,710		—
	Total short-term investments		272,555			—			272,555		—
	Long-term investments
	Corporate debt securities		61,704			—			61,704		—
	Government debt securities		28,963			—			28,963		—
	Municipal debt securities		8,476			—			8,476		—
	Derivative instrument		1,221			—			1,221		—
	Total long-term investments		100,364			—			100,364		—
	Total financial assets		$	426,700		$	35,795		$	390,905	$	—
						Fair Value Measurements at Reporting Date Using
	Description		December 31, 2013			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	20,172		$	20,172		$	—	$	—
	Municipal debt securities		23,506			—			23,506		—
	Total cash equivalents		43,678			20,172			23,506		—
	Short-term investments
	Municipal debt securities		122,325			—			122,325		—
	Commercial paper		75,911			—			75,911		—
	Corporate debt securities		45,134			—			45,134		—
	Government debt securities		10,008			—			10,008		—
	Total short-term investments		253,378			—			253,378		—
	Long-term investments
	Municipal debt securities		36,037			—			36,037		—
	Total long-term investments		36,037			—			36,037		—
	Total investment securities		$	333,093		$	20,172		$	312,921	$	—
	The Company had no transfers between Level 1 and Level 2 assets for the nine months ended September 30, 2014 and no significant transfers between Level 1 and Level 2 assets during the year ended December 31, 2013.
	The carrying amounts and estimated fair value of the Company's long-term debt (including current maturities), as well as the applicable fair value hierarchy tier, at September 30, 2014, are presented in the table below. The fair value of the Company’s publicly held long-term debt is 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 has categorized its publicly held debt as Level 2. The remaining six of the Company’s debt agreements are not publicly held. The Company has determined the estimated fair value of this debt to be Level 3, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes indicative pricing from counterparties and a discounted cash flow method to estimate the fair value of the Level 3 items.
		As of September 30, 2014
		Carrying value			Estimated fair value			Fair value level hierarchy
	5.50% Senior Notes, due July 2019	$	300,000		$	307,500		Level 2
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due November 2018	135,995			134,842			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	43,302			43,037			Level 3
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	41,053			40,753			Level 3
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	39,110			38,724			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	37,108			36,836			Level 3
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,748			9,679			Level 3
	Total	$	606,316		$	611,371

Derivative_Instruments

Derivative Instruments

9 Months Ended

Sep. 30, 2014

Derivative Instruments [Abstract]

'

Derivative Instruments and Hedging Activities Disclosure

'

Derivative Instruments

The Company is directly and indirectly affected by changes in certain market conditions. These changes in market conditions may adversely impact the Company's financial performance and are referred to as "market risks." When deemed appropriate, the Company will use derivatives as a risk management tool to mitigate the potential impact of certain market risks. The market risk managed by the Company through the use of a derivative instrument is foreign currency exchange rate risk. The Company is currently using a foreign currency swap which is a contract between two parties to exchange cash flows based on specified underlying notional amounts, assets and/or indices. The Company does not enter into derivative financial instruments for trading purposes.

For derivatives that will be accounted for as hedging instruments, the Company formally designates and documents, at inception, the financial instrument as a hedge of a specific underlying exposure, the risk management objective and the strategy for undertaking the hedge transaction. In addition, the Company formally assesses, both at inception and at least quarterly thereafter, whether the financial instruments used in hedging transactions are effective at offsetting changes in either the fair values or cash flows of the related underlying exposures. Any change in fair market value of any ineffective portion of a financial instrument is immediately recognized into earnings.

The Company determines the fair value of its derivative based on quoted market prices or pricing models using current market rates. Refer to Note 6 - Fair Value Measurements. The amounts exchanged are calculated by reference to the notional amounts and by other terms of the derivatives, such as interest rates, foreign currency exchange rates or other financial indices. The Company does not view the fair value of its derivative in isolation, but rather in relation to the fair value or cash flows of the underlying hedged transaction or other exposures. The Company's derivative is a straightforward over-the-counter instrument with liquid markets.

The following table presents the fair value of the Company's derivative instrument that was designated and qualified as part of a hedging relationship (in thousands):

Fair Value (1)(2)

Derivative Designated as Hedging Instrument

Balance Sheet Location (1)

September 30, 2014

December 31, 2013

Foreign currency swap

Deposits and other assets

$

1,221

$

—

(1) The Company's derivative instrument is carried at fair value in its consolidated balance sheet after considering the impact of legally enforceable master netting agreements and cash collateral held or placed with the same counterparties, as applicable. At September 30, 2014, no amounts were netted under a master netting arrangement and no collateral was held or placed with the counterparty.

(2) Refer to Note 6 - Fair Value Measurements for additional information related to the estimated fair value.

Cash Flow Hedging Strategy

The Company has entered into a foreign currency swap in order to mitigate the foreign currency exchange rate risk associated with the forecasted lease revenue from 12 Airbus A320 series aircraft leased to a European based company. The Company uses a cash flow hedge to minimize the variability in cash flows of assets or liabilities or forecasted transactions caused by fluctuations in foreign currency exchange rates. The change in the fair value of a derivative designated as a cash flow hedge is recorded in AOCI.

The Company maintains a foreign currency cash flow hedge to reduce the risk that its eventual U.S. dollar net cash inflows from leased aircraft outside the United States will be adversely affected by fluctuations in foreign currency exchange rates. The Company entered into a forward swap to hedge certain portions of forecasted cash flows denominated in euros. When the U.S. dollar strengthens against the foreign currency, the decline in the present value of future foreign currency cash flows is partially offset by gains in the fair value of the derivative instrument. Conversely, when the U.S. dollar weakens, the increase in the present value of future foreign currency cash flows is partially offset by losses in the fair value of the derivative instrument.

The total notional value of the Company's derivative instrument that was designated and qualified for the Company's foreign currency cash flow hedge was $1.2 million as of September 30, 2014.

The following table presents the pretax impact that changes in the fair values of the derivative instrument designated as a cash flow hedge had on AOCI during the three and nine months ended September 30, 2014 and 2013 (in thousands):

Gain (Loss) Recognized in Other Comprehensive Income ("OCI")

Three Months Ended September 30,

Nine Months Ended September 30,

2014

2013

2014

2013

Foreign currency swap

$

343

$

—

$

452

$

—

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	For the three and nine months ended September 30, 2014, the Company did not have any material unrecognized tax benefits. The Company’s policy is to recognize interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. There was no accrued interest or penalties at September 30, 2014.

Earnings_per_Share

Earnings per Share	9 Months Ended
	Sep. 30, 2014
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 awards. 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 two methods. Under both methods, the exercise of employee stock options and stock-settled stock appreciation rights are 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.
	Both methods resulted in the same diluted net income per share for the three months ended September 30, 2014 and 2013. For the nine months ended September 30, 2014 and 2013, 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 (shares shown in and below the following table are in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Basic:
	Net income attributable to Allegiant Travel Company	$	14,172		$	17,106		$	81,892		$	74,798
	Less: Net income allocated to participating securities	(90		)	(135		)	(586		)	(563		)
	Net income attributable to common stock	$	14,082		$	16,971		$	81,306		$	74,235
	Net income per share, basic	$	0.8		$	0.91		$	4.56		$	3.92
	Weighted-average shares outstanding	17,605			18,629			17,848			18,925
	Diluted:
	Net income attributable to Allegiant Travel Company	$	14,172		$	17,106		$	81,892		$	74,798
	Less: Net income allocated to participating securities	—			—			(584		)	(559		)
	Net income attributable to common stock	$	14,172		$	17,106		$	81,308		$	74,239
	Net income per share, diluted	$	0.8		$	0.91		$	4.54		$	3.9
	Weighted-average shares outstanding	17,605			18,629			17,848			18,925
	Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	99			165			101			151
	Adjusted weighted-average shares outstanding under treasury stock method	17,704			18,794			17,949			19,076
	Participating securities excluded under two-class method	N/A			N/A			(37		)	(34		)
	Adjusted weighted-average shares outstanding under two-class method	N/A			N/A			17,912			19,042
	Stock awards outstanding of 50 shares for the three months ended September 30, 2014 and 75 shares for the nine months ended September 30, 2014 were excluded from the computation of diluted earnings per share as they were antidilutive. For the three and nine months ended September 30, 2013, stock awards outstanding of 33 shares and 191 shares were excluded, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	As of September 30, 2014, the Company had firm commitments to purchase the following aircraft:
	Aircraft Type	Number of Firm Commitments
	Airbus A319	7
	Airbus A320	3
	The aircraft listed in the table above are scheduled for delivery starting in the last quarter of 2014 through 2016.
	The table below summarizes the Company's commitments as of September 30, 2014, which primarily relate to the acquisition of aircraft, aircraft improvements, operating lease obligations, and other commitments primarily to acquire information technology services and assets and other capital expenditure projects.
		As of September 30, 2014
	Last three months of 2014	$	73,987
	2015	156,993
	2016	47,303
	2017	6,286
	2018	46
	After 2018	91
	Total commitments	$	284,706
	As of September 30, 2014, the Company has adequate liquidity resourses and may use operating cash flows, future financing or cash balances to meet these future commitments. The Company can provide no assurance that financing for aircraft purchases will be available to the Company on acceptable terms when necessary or at all.
	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.

Related_Party

Related Party	9 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions Disclosure	'
	Related Party Transactions
	The buildings where the Company has maintained its headquarters and training facility during the nine months ended September 30, 2014 are leased from a limited liability company in which our Chief Executive Officer and one outside Director own a significant interest as non-controlling members. Under the terms of these agreements, the Company made rent payments totaling $2.5 million for the nine months ended September 30, 2014 and $2.1 million for the same period in 2013.
	For the nine months ended September 30, 2014, Game Plane, LLC, a wholly owned subsidiary of the Company, paid $3.0 million in program development costs to Alpine Labs, LLC. Alpine Labs, LLC has partnered with Game Plane, LLC to produce and distribute game shows filmed on Company flights. The game shows are part of promotional efforts for the Company. The Company’s Chairman and Chief Executive Officer owns a 25 percent interest in and is on the managing board of Alpine Labs, LLC.
	The Company, as part of its stock repurchase plan, agreed to repurchase all of Andrew Levy's, former President, Director, and Chief Operating Officer, previously unvested shares of restricted stock (23,623 shares) and all of his previously unexercised stock options (options to purchase 127,512 shares at exercise prices between $36.97 per share and $108.59 per share). The repurchases were made based on a stock price of $124.05 per share, which was the average closing price of the Company’s stock over the five trading days prior to the date of the separation agreement. As a result, the Company paid Mr. Levy approximately $8.5 million for the cancellation of these shares of restricted stock and stock options.
	During the quarter, the Company repurchased 200,000 shares of the Company's common stock from Maurice Gallagher, Chairman and Chief Executive Officer, as part of the Company's stock repurchase program. The price paid was $126.20 per share, based on the average closing price over the five days preceding the transaction for a total purchase price of $25.2 million.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	In October 2014, the Company purchased five additional buildings, totaling 82,000 square feet, adjacent to the Company's headquarters for approximately $10.1 million. The buildings are unencumbered and were acquired to facilitate the Company's future growth opportunities.
	In October 2014, the Company entered into an agreement to purchase two Airbus A320 series aircraft. The Company expects to take delivery of the two Airbus A320 series aircraft in 2016.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies - (Policies)	9 Months Ended
	Sep. 30, 2014
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. Investments in affiliates in which the Company’s ownership interest ranges from 20 to 50 percent and in which the Company has the ability to exercise significant influence over operating and financial policies are accounted for under the equity method. 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 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 condensed or 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, 2013, filed with the Securities and Exchange Commission.
Use of Estimates	'
	Use of estimates
	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 could differ from these estimates.
	The interim results reflected in the unaudited consolidated financial statements are not necessarily indicative of the results that may be expected for other interim periods or for the full year.
New Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board ("FASB") issued new guidance related to reporting discontinued operations. This new standard raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. The new standard is effective for fiscal years beginning on or after December 15, 2014. Early adoption is permitted but only for disposals that have not been reported in financial statements previously issued. The Company is evaluating the impact, if any, of adopting this new accounting standard on its financial statements.
	In May 2014, the FASB issued new accounting guidance related to revenue recognition. This new standard will replace all current U.S. GAAP guidance on this topic and eliminate all industry-specific guidance. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised 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. This guidance will be effective for the Company beginning January 1, 2017 and at that time, can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. The Company is evaluating the impact of adopting this new accounting standard on its financial statements.

Investment_Securities_Tables

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Summary of Investment Securities	'
	Investment securities consisted of the following:
		As of September 30, 2014									As of December 31, 2013
				Gross Unrealized									Gross Unrealized
		Cost		Gains		(Losses)			Market Value		Cost		Gains		(Losses)			Market Value
	Money market funds	$	35,795	$	—	$	—		$	35,795	$	20,172	$	—	$	—		$	20,172
	Certificates of deposit	10,038		3		—			10,041		—		—		—			—
	Commercial paper	66,956		6		(10		)	66,952		75,905		8		(2		)	75,911
	Municipal debt securities	137,936		30		(3		)	137,963		181,870		17		(19		)	181,868
	Government debt securities	28,992		—		(29		)	28,963		10,008		—		—			10,008
	Corporate debt securities	141,153		1		(99		)	141,055		45,150		—		(16		)	45,134
	Federal agency debt securities	$	4,709	$	1	$	—		$	4,710	$	—	$	—	$	—		$	—
	Total	$	425,579	$	41	$	(141	)	$	425,479	$	333,105	$	25	$	(37	)	$	333,093

Property_and_Equipment_Tables

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment	'
	Property and equipment consist of the following:
		As of September 30, 2014			As of December 31, 2013
	Flight equipment	$	936,462		$	629,715
	Ground property and equipment	90,065			73,638
	Total property and equipment	1,026,527			703,353
	Less accumulated depreciation and amortization	(309,469		)	(251,769		)
	Property and equipment, net	$	717,058		$	451,584

Property_and_Equipment_Types_o

Property and Equipment Types of Commercial Aircraft (Tables)	9 Months Ended
	Sep. 30, 2014
Types of Commercial Aircraft [Abstract]	'
Types of Commercial Aircraft	'
	The following table summarizes the Company's total aircraft fleet as of September 30, 2014:
	Aircraft Type	Owned (1)	Seating Capacity (per aircraft)	Average Age in Years
	MD-88/83	53	166	24.8
	B757-200	6	215	21.6
	A319 (2)	15	156	10
	A320	7	177	14
	Total aircraft	81

LongTerm_Debt_Tables

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Summary of Long-Term Debt	'
	Long-term debt consisted of the following:
		As of September 30, 2014		As of December 31, 2013
	5.50% Senior Notes, due July 2019	$	300,000	$	—
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due November 2018	135,995		—
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	43,302		48,000
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	41,053		—
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	39,110		45,775
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	37,108		—
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,748		9,953
	Senior secured term loan facility, interest at LIBOR plus 4.25% with LIBOR floor of 1.5%, due March 2017	—		121,230
	Note payable, secured by aircraft, interest at 4.65%, due July 2016	—		9,342
	Total long-term debt	606,316		234,300
	Less current maturities	51,895		20,237
	Long-term debt, net of current maturities	$	554,421	$	214,063

LongTerm_Debt_Schedule_of_Matu

Long-Term Debt Schedule of Maturities of Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2014
Schedule of Maturities of Long-Term Debt [Abstract]	'
Schedule of Maturities of Long-term Debt	'
	Maturities of long-term debt, as of September 30, 2014, for the remainder of 2014 and for the next four years and thereafter, in aggregate, are:
		September 30, 2014
	2014	$	13,200
	2015	53,879
	2016	55,554
	2017	57,323
	2018	112,601
	Thereafter	313,759
	Total	$	606,316

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Assets Measured at Fair Value On a Recurring Basis	'
	Assets measured at fair value on a recurring basis at September 30, 2014 and December 31, 2013 were as follows:
						Fair Value Measurements at Reporting Date Using
	Description		September 30, 2014			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	35,795		$	35,795		$	—	$	—
	Commercial paper		9,999			—			9,999		—
	Municipal debt securities		7,283			—			7,283		—
	Corporate debt securities		704			—			704		—
	Total cash equivalents		53,781			35,795			17,986		—
	Short-term investments
	Municipal debt securities		122,204			—			122,204		—
	Corporate debt securities		78,647			—			78,647		—
	Commercial paper		56,953			—			56,953		—
	Certificates of deposit		10,041			—			10,041		—
	Federal agency debt securities		4,710			—			4,710		—
	Total short-term investments		272,555			—			272,555		—
	Long-term investments
	Corporate debt securities		61,704			—			61,704		—
	Government debt securities		28,963			—			28,963		—
	Municipal debt securities		8,476			—			8,476		—
	Derivative instrument		1,221			—			1,221		—
	Total long-term investments		100,364			—			100,364		—
	Total financial assets		$	426,700		$	35,795		$	390,905	$	—
						Fair Value Measurements at Reporting Date Using
	Description		December 31, 2013			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	Cash equivalents
	Money market funds		$	20,172		$	20,172		$	—	$	—
	Municipal debt securities		23,506			—			23,506		—
	Total cash equivalents		43,678			20,172			23,506		—
	Short-term investments
	Municipal debt securities		122,325			—			122,325		—
	Commercial paper		75,911			—			75,911		—
	Corporate debt securities		45,134			—			45,134		—
	Government debt securities		10,008			—			10,008		—
	Total short-term investments		253,378			—			253,378		—
	Long-term investments
	Municipal debt securities		36,037			—			36,037		—
	Total long-term investments		36,037			—			36,037		—
	Total investment securities		$	333,093		$	20,172		$	312,921	$	—
Fair Value, Liabilities Measured on Recurring Basis	'
	The Company utilizes indicative pricing from counterparties and a discounted cash flow method to estimate the fair value of the Level 3 items.
		As of September 30, 2014
		Carrying value			Estimated fair value			Fair value level hierarchy
	5.50% Senior Notes, due July 2019	$	300,000		$	307,500		Level 2
	Notes payable, secured by aircraft, interest at LIBOR plus 3.08%, due November 2018	135,995			134,842			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.46%, due November 2019	43,302			43,037			Level 3
	Note payable, secured by aircraft, interest at LIBOR plus 2.95%, due April 2018	41,053			40,753			Level 3
	Notes payable, secured by aircraft, interest at 3.99%, due October 2018	39,110			38,724			Level 3
	Notes payable, secured by aircraft, interest at LIBOR plus 2.95%, due May 2018	37,108			36,836			Level 3
	Note payable, secured by real estate, interest at 2.86%, due October 2018	9,748			9,679			Level 3
	Total	$	606,316		$	611,371

Derivative_Instruments_Designa

Derivative Instruments Designated as Hedging (Tables)	9 Months Ended
	Sep. 30, 2014
Summary of Derivative Instruments by Hedge Designation [Abstract]	'
Derivative Instruments, Fair Value, Designated as Hedging Instruments	'
	The following table presents the fair value of the Company's derivative instrument that was designated and qualified as part of a hedging relationship (in thousands):
				Fair Value (1)(2)
	Derivative Designated as Hedging Instrument	Balance Sheet Location (1)		September 30, 2014			December 31, 2013
	Foreign currency swap	Deposits and other assets		$	1,221		$	—
Schedule of Cash Flow Hedges Gains or Losses Recognized in AOCI and Earnings	'
	The following table presents the pretax impact that changes in the fair values of the derivative instrument designated as a cash flow hedge had on AOCI during the three and nine months ended September 30, 2014 and 2013 (in thousands):
			Gain (Loss) Recognized in Other Comprehensive Income ("OCI")
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014		2013
	Foreign currency swap		$	343		$	—		$	452	$	—

Earnings_per_Share_Tables

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2014
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 (shares shown in and below the following table are in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Basic:
	Net income attributable to Allegiant Travel Company	$	14,172		$	17,106		$	81,892		$	74,798
	Less: Net income allocated to participating securities	(90		)	(135		)	(586		)	(563		)
	Net income attributable to common stock	$	14,082		$	16,971		$	81,306		$	74,235
	Net income per share, basic	$	0.8		$	0.91		$	4.56		$	3.92
	Weighted-average shares outstanding	17,605			18,629			17,848			18,925
	Diluted:
	Net income attributable to Allegiant Travel Company	$	14,172		$	17,106		$	81,892		$	74,798
	Less: Net income allocated to participating securities	—			—			(584		)	(559		)
	Net income attributable to common stock	$	14,172		$	17,106		$	81,308		$	74,239
	Net income per share, diluted	$	0.8		$	0.91		$	4.54		$	3.9
	Weighted-average shares outstanding	17,605			18,629			17,848			18,925
	Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	99			165			101			151
	Adjusted weighted-average shares outstanding under treasury stock method	17,704			18,794			17,949			19,076
	Participating securities excluded under two-class method	N/A			N/A			(37		)	(34		)
	Adjusted weighted-average shares outstanding under two-class method	N/A			N/A			17,912			19,042

Commitments_and_Contingencies_

Commitments and Contingencies Commitments to Purchase (Tables)	9 Months Ended
	Sep. 30, 2014
Commitments to Purchase Aircraft [Abstract]	'
Long-term Purchase Commitment	'
	As of September 30, 2014, the Company had firm commitments to purchase the following aircraft:
	Aircraft Type	Number of Firm Commitments
	Airbus A319	7
	Airbus A320	3

Commitments_and_Contingencies_1

Commitments and Contingencies Payments Related to Commitments to Purchase (Tables)	9 Months Ended
	Sep. 30, 2014
Payments Related to Commitments to Purchase [Abstract]	'
Long-term Purchase Commitment	'
	The table below summarizes the Company's commitments as of September 30, 2014, which primarily relate to the acquisition of aircraft, aircraft improvements, operating lease obligations, and other commitments primarily to acquire information technology services and assets and other capital expenditure projects.
		As of September 30, 2014
	Last three months of 2014	$	73,987
	2015	156,993
	2016	47,303
	2017	6,286
	2018	46
	After 2018	91
	Total commitments	$	284,706

Investment_Securities_Detail_I

Investment Securities (Detail) - Investment Securities (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Cost	$425,579	$333,105
Gross Unrealized Gains	41	25
Gross Unrealized Losses	141	37
Market Value	425,479	333,093
Money market funds	'	'
Cost	35,795	20,172
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Market Value	35,795	20,172
Certificates of deposit	'	'
Cost	10,038	0
Gross Unrealized Gains	3	0
Gross Unrealized Losses	0	0
Market Value	10,041	0
Commercial paper	'	'
Cost	66,956	75,905
Gross Unrealized Gains	6	8
Gross Unrealized Losses	10	2
Market Value	66,952	75,911
Municipal debt securities	'	'
Cost	137,936	181,870
Gross Unrealized Gains	30	17
Gross Unrealized Losses	3	19
Market Value	137,963	181,868
Government debt securities	'	'
Cost	28,992	10,008
Gross Unrealized Gains	0	0
Gross Unrealized Losses	29	0
Market Value	28,963	10,008
Corporate debt securities	'	'
Cost	141,153	45,150
Gross Unrealized Gains	1	0
Gross Unrealized Losses	99	16
Market Value	141,055	45,134
US Government Agencies Debt Securities	'	'
Cost	4,709	'
Gross Unrealized Gains	1	'
Gross Unrealized Losses	0	'
Market Value	$4,710	'

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	9 Months Ended			9 Months Ended					9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Aug. 05, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014	Oct. 31, 2014	Sep. 30, 2014
	aircraft	aircraft		MD-80 Aircraft	Boeing 757	Airbus A319	Airbus A320	Airbus A320 Aircraft Series	Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen	Subsequent Event	Capital Addition Purchase Commitments [Member]
				seats	seats	aircraft	aircraft		Airbus A320 Aircraft Series	Airbus A319	Airbus A320
				aircraft	aircraft	seats	seats			aircraft	aircraft
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Number Of Aircraft Committed To Purchase	'	8	'	'	'	7	3	'	'	2	2
Debt Instrument, Collateral	'	'	'	'	'	'	'	'	'1	'	'
Assets	$1,269,904	'	$930,191	'	'	'	'	$236,100	'	'	'
Secured Long-term Debt, Noncurrent	606,316	'	'	'	'	'	'	'	'	'	'
Number of Aircraft Owned	81	'	'	53	6	15	7	'	'	'	'
Seating Capacity	'	'	'	166	215	156	177	'	'	'	'
Average Age of Aircraft	'	'	'	'24 years 9 months 18 days	'21 years 7 months 6 days	'10 years	'14 years	'	'	'	'
Property, Plant and Equipment, Gross	936,462	'	629,715	'	'	'	'	'	'	'	'
Ground property and equipment	90,065	'	73,638	'	'	'	'	'	'	'	'
Property, Plant and Equipment, Gross	1,026,527	'	703,353	'	'	'	'	'	'	'	'
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-309,469	'	-251,769	'	'	'	'	'	'	'	'
Property, Plant and Equipment, Net	$717,058	'	$451,584	'	'	'	'	'	'	'	'

LongTerm_Debt_LongTerm_Debt_Co

Long-Term Debt Long-Term Debt - Components of Long-Term Debt (Detail) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Nov. 30, 2013

Sep. 30, 2014

Apr. 30, 2014

Dec. 31, 2013

Dec. 31, 2013

Oct. 31, 2013

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Jun. 20, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

31-May-14

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

In Thousands, unless otherwise specified

Due July 2019

Due July 2019

Due July 2019

Due November 2019

Due November 2019

Due November 2019

Due April 2018

Due April 2018

Due April 2018

Due October 2018

Due October 2018

Due October 2018

Due March 2017

Due March 2017

Due July 2016

Due July 2016

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Due November 2018

Due November 2018

Due November 2018

Due October 2018

Due October 2018

Due May 2018

Due May 2018

Due May 2018

Due October 2018

Due October 2018

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Secured Long-term Debt, Noncurrent

$606,316

'

$300,000

$300,000

$0

$43,302

$48,000

$48,000

$41,053

$45,300

$0

'

$10,000

$48,000

$0

$121,230

$0

$9,342

$135,995

$142,000

$0

$39,110

$45,775

$37,108

$40,000

$0

$9,748

$9,953

Long-term Debt, Fair Value

606,316

234,300

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Less current maturities

51,895

20,237

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, net of current maturities

$554,421

$214,063

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest Rate

'

'

5.50%

5.50%

0.00%

2.46%

2.46%

2.46%

2.95%

'

0.00%

2.86%

2.86%

3.99%

0.00%

4.25%

0.00%

4.65%

3.08%

'

0.00%

3.99%

3.99%

2.95%

'

2.95%

2.86%

'

Notes Payable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.00%

1.50%

'

'

'

'

'

'

'

'

'

'

'

'

LongTerm_Debt_Detail

Long-Term Debt (Detail) (USD $)

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Apr. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Dec. 31, 2013

Oct. 31, 2013

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Jun. 20, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

31-May-14

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2013

Due July 2016

Due July 2016

Due March 2017

Due March 2017

Due April 2018

Due April 2018

Due April 2018

Due July 2019

Due July 2019

Due July 2019

Due October 2018

Due October 2018

Due October 2018

MD-80 Aircraft

Boeing 757

Boeing 757

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

aircraft

aircraft

Due July 2019

Due November 2018

Due November 2018

Due November 2018

Airbus A320 Aircraft Series

Due November 2018

Due May 2018

Due May 2018

Due May 2018

Due October 2018

Due October 2018

Airbus A320

Due October 2018

Due October 2018

Airbus A320

aircraft

aircraft

aircraft

Number Of Aircraft Used As Collateral

'

'

'

'

'

'

'

'

'

'

'

'

'

'

53

6

2

'

'

'

'

'

'

'

'

'

'

4

'

'

4

Debt Instrument LIBOR Percentage Rate Minimum

'

'

'

0.00%

1.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Secured Long-term Debt, Noncurrent

$606,316,000

$0

$9,342,000

$0

$121,230,000

$41,053,000

$45,300,000

$0

$300,000,000

$300,000,000

$0

'

$10,000,000

$48,000,000

'

'

'

$135,995,000

$142,000,000

$0

'

'

$37,108,000

$40,000,000

$0

$39,110,000

$45,775,000

'

$9,748,000

$9,953,000

'

Debt Instrument, Collateral

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'12

'

'

'1

'

'

'

'

'

'

'

'

'

'

Interest Rate

'

0.00%

4.65%

0.00%

4.25%

2.95%

'

0.00%

5.50%

5.50%

0.00%

2.86%

2.86%

3.99%

2.95%

'

'

3.08%

'

0.00%

'

3.08%

2.95%

'

2.95%

3.99%

3.99%

'

2.86%

'

'

Repayments of Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$8,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

LongTerm_Debt_Schedule_of_Matu1

Long-Term Debt Schedule of Maturities of Long-Term Debt (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$13,200	'
Long-term Debt, Maturities, Repayments of Principal in Year Two	53,879	'
Long-term Debt, Maturities, Repayments of Principal in Year Three	55,554	'
Long-term Debt, Maturities, Repayments of Principal in Year Four	57,323	'
Long-term Debt, Maturities, Repayments of Principal in Year Five	112,601	'
Long-term Debt, Maturities, Repayments of Principal after Year Five	313,759	'
Long-term Debt, Fair Value	$606,316	$234,300

Stockholders_Equity_Detail

Stockholders' Equity (Detail) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Stock Repurchased During Period, Shares	'	880,991
Treasury Stock Acquired, Average Cost Per Share	'	$85.64
Stock Repurchased During Period Through Private Transactions, Shares	246,431	'
Total Stock Repurchased, Shares	1,199,740	'
Payments for Repurchase of Common Stock	$129,323	$79,990
PaymentOfDividendsParticipatingSecurities	41,787	0
Open Market Purchases	'	'
Stock Repurchased During Period, Shares	953,309	'
Treasury Stock Acquired, Average Cost Per Share	$103.44	'
Stock Repurchased During Period, Value	$98,606	$75,449

Fair_Value_Measurements_Detail

Fair Value Measurements (Detail) - Fair Value Measurements at Reporting Date Using (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investment Securities	$425,479	$333,093
Fair Value, Measurements, Recurring | Estimate of Fair Value	'	'
Cash Equivalents	53,781	43,678
Investment Securities	272,555	253,378
Derivative Asset	1,221	'
Investments, Fair Value Disclosure	100,364	36,037
Assets, Fair Value Disclosure	426,700	333,093
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1	'	'
Cash Equivalents	35,795	20,172
Investment Securities	0	0
Derivative Asset	0	'
Investments, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	35,795	20,172
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2	'	'
Cash Equivalents	17,986	23,506
Investment Securities	272,555	253,378
Derivative Asset	1,221	'
Investments, Fair Value Disclosure	100,364	36,037
Assets, Fair Value Disclosure	390,905	312,921
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3	'	'
Cash Equivalents	0	0
Investment Securities	0	0
Derivative Asset	0	'
Investments, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Money market funds | Estimate of Fair Value	'	'
Cash Equivalents	35,795	20,172
Fair Value, Measurements, Recurring | Money market funds | Fair Value, Inputs, Level 1	'	'
Cash Equivalents	35,795	20,172
Fair Value, Measurements, Recurring | Money market funds | Fair Value, Inputs, Level 2	'	'
Cash Equivalents	0	0
Fair Value, Measurements, Recurring | Money market funds | Fair Value, Inputs, Level 3	'	'
Cash Equivalents	0	0
Fair Value, Measurements, Recurring | Commercial paper | Estimate of Fair Value	'	'
Cash Equivalents	9,999	'
Investment Securities	56,953	75,911
Fair Value, Measurements, Recurring | Commercial paper | Fair Value, Inputs, Level 1	'	'
Cash Equivalents	0	'
Investment Securities	0	0
Fair Value, Measurements, Recurring | Commercial paper | Fair Value, Inputs, Level 2	'	'
Cash Equivalents	9,999	'
Investment Securities	56,953	75,911
Fair Value, Measurements, Recurring | Commercial paper | Fair Value, Inputs, Level 3	'	'
Cash Equivalents	0	'
Investment Securities	0	0
Fair Value, Measurements, Recurring | Municipal debt securities | Estimate of Fair Value	'	'
Cash Equivalents	7,283	23,506
Investment Securities	122,204	122,325
Investments, Fair Value Disclosure	'	36,037
Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 1	'	'
Cash Equivalents	0	0
Investment Securities	0	0
Investments, Fair Value Disclosure	'	0
Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 2	'	'
Cash Equivalents	7,283	23,506
Investment Securities	122,204	122,325
Investments, Fair Value Disclosure	'	36,037
Fair Value, Measurements, Recurring | Municipal debt securities | Fair Value, Inputs, Level 3	'	'
Cash Equivalents	0	0
Investment Securities	0	0
Investments, Fair Value Disclosure	'	0
Fair Value, Measurements, Recurring | Corporate debt securities | Estimate of Fair Value	'	'
Cash Equivalents	704	'
Investment Securities	78,647	45,134
Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 1	'	'
Cash Equivalents	0	'
Investment Securities	0	0
Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 2	'	'
Cash Equivalents	704	'
Investment Securities	78,647	45,134
Fair Value, Measurements, Recurring | Corporate debt securities | Fair Value, Inputs, Level 3	'	'
Cash Equivalents	0	'
Investment Securities	0	0
Fair Value, Measurements, Recurring | Government debt securities | Estimate of Fair Value	'	'
Investment Securities	'	10,008
Fair Value, Measurements, Recurring | Government debt securities | Fair Value, Inputs, Level 1	'	'
Investment Securities	'	0
Fair Value, Measurements, Recurring | Government debt securities | Fair Value, Inputs, Level 2	'	'
Investment Securities	'	10,008
Fair Value, Measurements, Recurring | Government debt securities | Fair Value, Inputs, Level 3	'	'
Investment Securities	'	0
Fair Value, Measurements, Recurring | Certificates of deposit | Estimate of Fair Value	'	'
Investment Securities	10,041	'
Fair Value, Measurements, Recurring | Certificates of deposit | Fair Value, Inputs, Level 1	'	'
Investment Securities	0	'
Fair Value, Measurements, Recurring | Certificates of deposit | Fair Value, Inputs, Level 2	'	'
Investment Securities	10,041	'
Fair Value, Measurements, Recurring | Certificates of deposit | Fair Value, Inputs, Level 3	'	'
Investment Securities	0	'
Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Estimate of Fair Value	'	'
Investment Securities	4,710	'
Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Fair Value, Inputs, Level 1	'	'
Investment Securities	0	'
Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Fair Value, Inputs, Level 2	'	'
Investment Securities	4,710	'
Fair Value, Measurements, Recurring | US Government Agencies Debt Securities | Fair Value, Inputs, Level 3	'	'
Investment Securities	0	'
Long Term Investments | Municipal debt securities | Estimate of Fair Value	'	'
Investment Securities	8,476	'
Long Term Investments | Municipal debt securities | Fair Value, Inputs, Level 1	'	'
Investment Securities	0	'
Long Term Investments | Municipal debt securities | Fair Value, Inputs, Level 2	'	'
Investment Securities	8,476	'
Long Term Investments | Municipal debt securities | Fair Value, Inputs, Level 3	'	'
Investment Securities	0	'
Long Term Investments | Corporate debt securities | Estimate of Fair Value	'	'
Investment Securities	61,704	'
Long Term Investments | Corporate debt securities | Fair Value, Inputs, Level 1	'	'
Investment Securities	0	'
Long Term Investments | Corporate debt securities | Fair Value, Inputs, Level 2	'	'
Investment Securities	61,704	'
Long Term Investments | Corporate debt securities | Fair Value, Inputs, Level 3	'	'
Investment Securities	0	'
Long Term Investments | Government debt securities | Estimate of Fair Value	'	'
Investment Securities	28,963	'
Long Term Investments | Government debt securities | Fair Value, Inputs, Level 1	'	'
Investment Securities	0	'
Long Term Investments | Government debt securities | Fair Value, Inputs, Level 2	'	'
Investment Securities	28,963	'
Long Term Investments | Government debt securities | Fair Value, Inputs, Level 3	'	'
Investment Securities	$0	'

Fair_Value_Measurements_Estima

Fair Value Measurements Estimated Fair Value of Debt (Details) (USD $)

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Jun. 20, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

31-May-14

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Nov. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Apr. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Oct. 31, 2013

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

In Thousands, unless otherwise specified

Fair Value, Measurements, Recurring

Due July 2019

Due July 2019

Due July 2019

Due July 2019

Due November 2018

Due November 2018

Due November 2018

Due November 2018

Due May 2018

Due May 2018

Due May 2018

Due May 2018

Due November 2019

Due November 2019

Due November 2019

Due November 2019

Due April 2018

Due April 2018

Due April 2018

Due April 2018

Due October 2018

Due October 2018

Due October 2018

Due October 2018

Due October 2018

Due October 2018

Due October 2018

Due October 2018

Corporate debt securities

Fair Value, Measurements, Recurring

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Fair Value, Measurements, Recurring

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Fair Value, Measurements, Recurring

Fair Value, Measurements, Recurring

Fair Value, Measurements, Recurring

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Fair Value, Measurements, Recurring

Fair Value, Measurements, Recurring

Corporate debt securities

Corporate debt securities

Corporate debt securities

Corporate debt securities

Corporate debt securities

Corporate debt securities

Corporate debt securities

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen

Notes Payable, Two Point Nine Five Percent, Due May Two Thousand Eighteen

Notes Payable, Three Point Nine Nine Percent, Due October Two Thousand Eighteen

Notes Payable, Two Point Eight Six Percent, Due October Two Thousand Eighteen

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Secured Long-term Debt, Noncurrent

$606,316

'

$300,000

$300,000

$0

'

$135,995

$142,000

$0

'

$37,108

$40,000

$0

'

$43,302

$48,000

$48,000

'

$41,053

$45,300

$0

'

$10,000

$48,000

$39,110

$45,775

$9,748

$9,953

'

'

Secured Long-term Debt, Noncurrent

'

$611,371

'

'

'

$307,500

'

'

'

$134,842

'

'

'

$36,836

'

'

'

$43,037

'

'

'

$40,753

'

'

'

'

'

'

$38,724

$9,679

Derivative_Instruments_Derivat

Derivative Instruments Derivative Instruments - Textuals (Details) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Summary of Derivative Instruments by Hedge Designation [Abstract]	'
Derivative, Notional Amount	$1.20

Derivative_Instruments_Derivat1

Derivative Instruments Derivative Designated as Hedging (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Summary of Derivative Instruments by Hedge Designation [Abstract]	'	'
Derivative Asset	$1,221	$0

Derivative_Instruments_Pretax_

Derivative Instruments Pretax Impact of Derivative Instrument on AOCI (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Pretax Impact of Derivative Instrument on AOCI [Abstract]	'	'	'	'	'
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$343	$0	$452	$0	'
Derivative Asset	$1,221	'	$1,221	'	$0

Income_Taxes_Income_Taxes_Deta

Income Taxes Income Taxes (Details) (Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen, Due November 2018)	9 Months Ended
	Sep. 30, 2014
Notes Payable, Three Point Zero Eight Percent, Due May Two Thousand Eighteen | Due November 2018	'
Debt Instrument, Collateral	'12

Earnings_per_Share_Detail_Earn

Earnings per Share (Detail) - Earnings Per Share (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basic:	'	'	'	'
Net income attributable to Allegiant Travel Company (in Dollars)	$14,172	$17,106	$81,892	$74,798
Net income attributable to common stock (in Dollars)	14,172	17,106	81,308	74,239
Net income per share, diluted (in Dollars per share)	$0.80	$0.91	$4.54	$3.90
Net income attributable to common stock (in Dollars)	14,082	16,971	81,306	74,235
Net income per share, basic (in Dollars per share)	$0.80	$0.91	$4.56	$3.92
Weighted-average shares outstanding	17,605	18,629	17,848	18,925
Dilutive effect of stock options, restricted stock and stock-settled stock appreciation rights	99	165	101	151
Adjusted weighted-average shares outstanding under treasury stock method	17,704	18,794	17,949	19,076
Participating securities excluded under two-class method	'	'	-37	-34
Two-Class Method, Weighted Average Number of Shares Outstanding, Diluted	'	'	17,912	19,042
Basic	'	'	'	'
Basic:	'	'	'	'
Less: Net income allocated to participating securities (in Dollars)	90	135	586	563
Diluted	'	'	'	'
Basic:	'	'	'	'
Less: Net income allocated to participating securities (in Dollars)	$0	$0	$584	$559

Earnings_per_Share_Details_Tex

Earnings per Share (Details Textual)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings per Share (Textual) [Abstract]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	50	33	75	191

Commitments_and_Contingencies_2

Commitments and Contingencies (Detail)	Aug. 05, 2014	Sep. 30, 2014	Sep. 30, 2014
	aircraft	Airbus A319	Airbus A320
		aircraft	aircraft
Long-term Purchase Commitment [Line Items]	'	'	'
Number Of Aircraft Committed To Purchase	8	7	3

Commitments_and_Contingencies_3

Commitments and Contingencies Payments Related to Commitments to Purchase (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Payments Related to Commitments to Purchase [Abstract]	'
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	$73,987
Unrecorded Unconditional Purchase Obligation, Due within Two Years	156,993
Unrecorded Unconditional Purchase Obligation, Due within Three Years	47,303
Unrecorded Unconditional Purchase Obligation, Due within Four Years	6,286
Unrecorded Unconditional Purchase Obligation, Due within Five Years	46
Unrecorded Unconditional Purchase Obligation, Due after Five Years	91
Unrecorded Unconditional Purchase Obligation	$284,706

Related_Party_Details

Related Party (Details) (USD $)	9 Months Ended				3 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014
		Office Space	Office Space	Game Plane, LLC	Chief Executive Officer	Chief Executive Officer	Chief Operating Officer	Maximum	Minimum
						Beneficial Owner	Beneficial Owner	Chief Operating Officer	Chief Operating Officer
						Stock Ownership	Stock Ownership	Beneficial Owner	Beneficial Owner
								Stock Ownership	Stock Ownership
Related Party Transaction [Line Items]	'	'	'	'	'	'	'	'	'
Related Party Transaction, Amounts of Transaction	'	$2,500,000	$2,100,000	$3,000,000	'	'	'	'	'
Related Party, Ownership Percentage	'	'	'	'	'	25.00%	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	'	'	'	'	'	'	23,623	'	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	'	'	'	'	'	'	127,512	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	'	'	'	'	'	'	'	$108.59	$36.97
Accelerated Share Repurchases, Final Price Paid Per Share	'	'	'	'	$126.20	'	$124.05	'	'
Total Stock Repurchased, Shares	1,199,740	'	'	'	200,000	'	'	'	'
Total Stock Repurchased, Value	'	'	'	'	$25,200,000	'	$8,500,000	'	'

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	Aug. 05, 2014	Oct. 31, 2014	Sep. 30, 2014	Oct. 31, 2014
	aircraft	Building	Airbus A319	Airbus A319
		Subsequent Event	aircraft	Subsequent Event
				aircraft
Subsequent Event [Line Items]	'	'	'	'
Number of Buildings Purchased, Total	'	5	'	'
Square Footage of Buildings Purchased, Total	'	$82,000	'	'
Payments to Acquire Buildings	'	$10,100,000	'	'
Number Of Aircraft Committed To Purchase	8	'	7	2